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it# 































THE CHEMISTRY 


OF GAS MANUFACTURE 






The Chemistry 

OF 

Gas Manufacture 

A PRACTICAL MANUAL 

FOR THE USE OF 

GAS ENGINEERS , GAS MANAGERS , AND STUDENTS 


BY 

HAROLD M. ROYLE, F.C.S., 

\\ 

Chief Chemical Assistant at the Beckton Gas Works 


HCUtb Coloured plate and IRumerous illustrations 


NEW YORK 

THE NORMAN W. HENLEY PUBLISHING CO. 
132 NASSAU STREET 
LONDON 

CROSBY LOCKWOOD AND SON 
1908 





• ' 



PREFACE. 


J N the present volume—which may be described 
as a small work upon an inexhaustible subject 
—the Author’s aim has been to confine the work 
strictly to certain aspects of the Chemistry of Gas 
Manufacture, leaving the operations of manufacture 
alone. 

A knowledge of the elementary truths and 
processes of Chemistry being pre-supposed, he has 
endeavoured to furnish the working gas engineer 
and manager with a concise manual, covering ques¬ 
tions and points requiring attention .in the ordinary 
course of his duties, which, it is believed, will be 
found of practical utility, especially in those gas 
works where the operations are not of so great 
an extent as to necessitate the employment of a 
separate chemical staff. 

The volume, it is hoped, should also prove of 
utility to students of Gas Manufacture as well as to 
managers, as preparatory to the study of works of 
a larger scope. 



VI 


PREFACE. 


For convenience of reference, the several sub¬ 
jects specifically treated of—including Coal and its 
characteristics, Furnace Gases, Products of Carbon¬ 
isation, Materials for Purification, Fire-Bricks and 
Fire-Clay, Photometry and Gas Testing, Car- 
buretted Water-Gas, &c.—are dealt with in separate 
chapters (see “Contents”) ; while in the Appendices 
are given carefully selected extracts from matter 
previously published elsewhere, including the official 
regulations and instructions for testing coal-gas for 
illuminating power, calorific value and impurities, 
useful tables, data, statistics, &c. 

For some of the illustrations the Author is 
indebted to the kindness of manufacturers of the 
apparatus illustrated, and he takes this opportunity 
of expressing his thanks. 

For any practical suggestion for the improve¬ 
ment of the work with which readers thereof, or 
any of his professional brethren, may be disposed to 
favour him, the Author will be sincerely grateful : 
and all such communications will have his very 
careful consideration with a view to future editions. 

HAROLD M. ROYLE. 


Gas Works, 

Beckton, September 1907 . 


TABLE OF CONTENTS. 


CHAPTER I.—PREPARATION OF STANDARD SOLUTIONS. 

Designation of Normal Solution—Combining Weights of Reagents — 
Univalent, Bivalent, Trivalent Substances—Indicators : Cochi¬ 
neal Solution—Methyl Orange—Phenolphthalein—Litmus Solu¬ 
tion—Lacmoid—Sodium Carbonate — Ammonia — Ammonium 
Oxalate — Ammonium Sulphate — Ammonium Thiocyanate— 
Barium Hydroxide—Bromine Water—Calcium Hydroxide— 
Hydrochloric Acid—Potassium Hydroxide—Potassium Dichro¬ 
mate—Potassium Permanganate—Sodium Hydroxide—Sodium 
Thiosulphate—Iodine—Silver Nitrate—Di-tri-ortho-phosphate - 

CHAPTER II.—COAL. 

Decomposition of Fibrous Matter—Table of Decomposition of 
Fibrous Matter (Cellulose) to Graphite—Peat—Caking Coals— 
Non-Caking Coals—Cannel Coals—Coal Testing Plant—Test 
for C0 2 and H 2 S—Working Data—Estimation of C0 2 and SH 2 
—Analysis of Coals—Coke as Fuel—Tabulated Report on a 
Sample of Coal—Moisture in Coal and Coke—Sulphur in Coal 
and Coke—Phosphorus in Coal and Coke—Ash in Coke — 
Volatile Matter and Fixed Carbon—Specific Gravity—Nitrogen 
—Arsenic — Lewis Thompson’s Calorimeter — Mahler-Donkin 
Bomb Calorimeter --------- 

CHAPTER III.—FURNACES—TESTING AND REGULATION. 

Direct Coke-fired Setting—Generator Type—Regenerator Type— 
Tight Clinkering Door—Gaseous Firing—Sectional Elevation 
of Retort Setting—Generator Setting—Secondary Air and Waste 
Gas Flue—Analysis of Furnace Gases—“ Orsat Muencke” Ap¬ 
paratus— Determination of C0 2 ; 0 2 ; CO—Interpretation of 
Results—Analysis of Coke—Calorific Value of Various Con¬ 
stituents—Reaction in Producer—Setting of Damper—Watkins’ 
Patent Heat Recorders—Seger’s Cones—Siemens’ Electrical 
Pyrometer—Fery Radiation Pyrometer—Wanner Pyrometer— 
Sarco C0 2 Recorder—Simmance & Abady C0 2 Combustion 
Recorder and Draught. 


PAGES 


1-6 


7-36 


376-8 




CONTENTS. 


viii 


CHAPTER IV.—PRODUCTS OF CARBONISATION. 

Yield of Gas according to Temperature—Effects of Heat on Specific 
Gravity of Tar—Effects of Heat on Gas and Bye-Products— 
Effects of Heat-on Residuals—Nitrogen in Coal and Coke—List 
of Compounds in Coal-Tar—Distillation of Coal-Tar—Fractions 
—Crude Anilene Benzol—Phenols—Anthracene Oil—Pitch— 
Specific Gravity—Free Carbon—Hochst Test for Anthracene- 
Benzene— Estimation of Sulphur in Benzene — Ammonium 
Sulphate—Fertilisers and Feeding Stuffs Act, 1906 —Moisture 
in Sulphate—Ammonia in Sulphate - 


CHAPTER V.—ANALYSIS OF CRUDE COAL-GAS. 

Impurities in Coal Gas—Ammonia—Carbonic Acid and Sulphuretted 
Hydrogen—Separated Test for Carbonic Acid and Sulphuretted 
Hydrogen—Carbon Disulphide—Cyanogen—Prussian Blue 


CHAPTER VI.—ANALYSIS" OF LIME. 

Flare Lime—Kiln Lime—Scheibler’s Calcimeter—Schrotter Ap¬ 
paratus—Apparatus for Determining the C0 2 —Quantitative 
Method for Total Lime—Estimation of Calcium—Estimation of 
Silica and Alumina—Separation of Iron and Alumina—Estima¬ 
tion of Ca(OH ) 2 in Spent Lime. 


CHAPTER VII.—AMMONIA. 

Recovery and Production of Ammonia—Total Nitrogen in Coal— 
Ammonium Salts Volatile at Ordinary Temperatures—Fixed at 
Ordinary Temperatures — Analysis of Gasworks Liquor — 
Twaddell’s Hydrometer—Standard Acid—Distillation Test — 
Ammonia Free—Ammonia Fixed—Carbonic Acid—Chloride— 
Sulphur as Sulphate—As Sulphocyanide—As Sulphide, Sulphite, 
and Thiosulphate—As Sulphite and Thiosulphate—Total Sul¬ 
phur—As Polysulphide—Estimation of Sulphite—Estimation of 
Sulphite by Polysulphide Method—Distribution of Sulphur in 
Ammoniacal Liquor—Estimation of Cyanogen Compounds in 
Ammoniacal Liquor—Ferrocyanide—Thiocyanate (Ferrocyanide 
absent)—Thiocyanate (Ferrocyanide present) — Reaction of 
Cyanide and Polysulphide. 


PAGES 


69-91 


92-101 


102-111 


112-137 



CONTENTS. 


IX 


CHAPTER VIII.—ANALYSIS OF OXIDE OF IRON. 

PAGES 

Hydrated Oxide of Iron—Oxides of Iron—Moisture—Organic Matter 
—Ferric Oxide—Analysis—Fouling a Sample—Estimation of 
FeO—Estimation of Free Moisture—Estimation of Combined 
Waters—Calculated Hydrated Ferric Oxide .... 138-150 


CHAPTER IX.—NAPHTHALENE. 

olman and Smith Test—Dickenson-Gair Test—Somerville Test— 

Removal of Naphthalene — Botley Process—Carpenter’s Re¬ 
versible Condensers—Colman “Cyclone”—Young and Glover— 

Coulson—Bell’s Process.151-163 


CHAPTER X.—ANALYSES OF FIRE-BRICKS AND FIRE¬ 
CLAY, WELDON, AND SPENT OXIDE. 

Composition of Fire-Clays—Method of Analysis—Silica—Alumina 
and Ferric Oxide — Calcium — Magnesium — Potassium and 
Sodium — Specific Gravity, Volume, Weight, and Porosity — 

Analysis of Weldon Mud—Estimation of Water—Manganese 
Dioxide—Fouling of Weldon Mud—Analysis of Spent Oxide— 
Estimation of Sulphur—Estimation of Prussian Blue - - - 164-176 


CHAPTER XI.—PHOTOMETRY AND GAS TESTING. 

“Kepler’s Law of Inverse Squares”—“Lambert’s Cosine Law”— 

“ Generalised Photometrical Law ”—Methven Screen—Photo- 
metrical Testing—Letheby-Bunsen Photometer—Candle Balance 
—Testing with Candle—Five Cubic Foot Rate—Sixteen-Candle 
Basis—Flicker Photometer—Street Photometry—Factors for 
Different Angles—Factors for Longitudes and Horizontal Angles 
—Heating Value of Gas—Simmance-Abady Calorimeter—Junker 
Calorimeter—Candles and Calories—Calorific Value of Coal-Gas 
—Calorific Value of Carburetted Water-Gas—Flame Tempera¬ 
ture—Calorific Power of Fuels—Gas Analysis—Estimation of 
Benzene Vapour—Estimation of C 0 2 —Estimation of 0 2 — 
Estimation of CO—Estimation of Hydrogen and CO—Specific 
Gravity of Gases—Bunsen Effusion Test—Letheby Specific 
Gravity Globe—Schilling Diffusion Test—Lux Gas Balance— 
Simmance-Abady Portable Specific Gravity Bell - - - 177-224 


X 


CONTENTS. 


CHAPTER XII.—CARBURETTED WATER-GAS. 

Specific Gravity— Flash-Point, Abel Apparatus — Pensky-Martin 
Apparatus — Distillation of Oil — Sample of Russian Oil — 
Sample of American Oil—Composition and Valuation of Oils 
used for Gas Making—Bye-Product—Oil-Gas Tar—Distillation 
of Oil-Gas Tar—Oil-Gas Tar for Dust Laying - 


APPENDIX A.—METROPOLIS GAS. 

List of Testing Places—The Service Pipe to the Testing Places— 
Standard Lamp for Testing Illuminating Power—Time and 
Mode for Testing for Illuminating Power with Argand—Time 
and Mode for Testing for Illuminating Power with Flat Flame— 
Time and Mode for Testing for Sulphuretted Hydrogen—Mode for 
Testing for Sulphur Compounds other than Sulphuretted Hydro¬ 
gen—Mode of Testing for Calorific Power—Mode of Testing for 
Pressure—Meters—The Ten-Candle Pentane Lamp—Pentane : 
Preparation and Testing—Provision of Pentane—The Table 
Photometer—The Gas Meter—The Gas Governor—The Regu¬ 
lating Tap—The Metropolitan Argand Burner No. 2, and 
Sliding Base—The Flat Flame Burner and Sliding Base—The 
Slide, Scale, &c.—The Connecting Pipes—The Ten-Candle 
Pentane Lamp—The Photoped—The Aerorthometer—The Stop 
Clock—Dark Screens, Mirror, Measuring Rod—The Metropolitan 
Argand Burner No. 2—The Aerorthometer—Tabular Numbers— 
Test for Sulphuretted Hydrogen—Sulphur Test—The Gas 
Calorimeter and Form for Calculations—Street Lamp Pressure 
Gauge—One-Twelfth of a Cubic Foot Measure—Forms for 
Returns—Loan Apparatus ....... 


APPENDIX B.—MISCELLANEOUS EXTRACTS. 

Cyanogen in Purifying Materials and the Influence of Ammonia upon 
its Formation in Purification—The Chemical Composition and 
Technical Analysis of Water-Gas—Estimation of Ferrocyanide 
in Spent Oxide—Prussian Blue in Spent Oxide by Feld’s Method 
—Monazite Sands—Humidity, Effect of, on the Pentane Lamp— 
Estimation of Carbon Bisulphide in Benzene—Estimation of CS» 
and S in Commercial Benzene—Test for CN in Presence of HCN 
—Estimation of Benzol in Gas. 


PAGES 


225-238 


239-287 


288-294 





CONTENTS. 


APPENDIX C.—USEFUL TABLES, &c. 

Weights and Measures—Comparison of Thermometers—Comparison 
of Different Hydrometers—Specific Gravity and Weights of Gases 
—Specific Heat—Specific Gravity and Weights of Various 
Liquids—Densities and Weights of Gases and Vapours—Specific 
Gravities and Weights of Gases and Vapours— Specific Gravity 
of Liquor Ammonia—Calorific Power of Various Combustibles— 
Volumes of Water at Different Temperatures—Specific Gravity 
of Sulphuric Acid—Specific Gravity and Percentage of Caustic 
Soda—Specific Gravity and Percentage of Caustic Potash— 
Tension of Aqueous Vapour—Loss of Illuminating Power by 
Admixture of Air—Maximum Vapour Pressures of Naphthalene 
—Solubility of Gases in Water—Atomic Weights—Percentage 
by Volume, Corresponding to the Weight in Grains of C 0 2 per 
Cubic Foot of Gas—Ditto SH 2 —Ditto NH 3 —Notes on Calorific 
Value. 

INDEX. - 


xi 

PAGES 


295-316 

317-328 







LIST OF ILLUSTRATIONS. 


FIG. 

I. 

Apparatus used for Experimentally Testing a Sample of Coal 

, 

_ 

PAGE 

13 

2. 

Apparatus used for Estimation of Moisture in Coal - 

- 

- 

22 

3 - 

Desiccator used for Estimation of Moisture in Coal - 

- 

. 

23 

4 - 

Muffle Furnace for Estimation of Ash in Coke 

- 

. 

25 

5 - 

Apparatus used for Estimation of Specific Gravity of Coal 

- 

- 

26 

6. 

Apparatus for Estimating Arsenic in Fuel 

- 

- 

29 

7 - 

Lewis Thompson’s Fuel Calorimeter - 

- 

- 

32 

8. 

Mahler-Donkin Bomb Calorimeter. 

- 

- 

35 

9 - 

Tight Clinkering Door, showing Primary Air Ports - 

- 

- 

38 

IO. 

Sectional Elevation of Retort Setting - 

- 

- 

40 

11. 

Do. do. do. showing Flues and Passages 

- 

41 

12. 

Showing Dividing Walls for Waste Gas Flue - 

- 

- 

42 

13 - 

“ Orsat Muencke ” Apparatus. 

- 

- 

45 

14. 

Watkins’ Patent Heat Recorder. 

- 

- 

49 

IS- 

Seger’s Cones in use. 



53 

16. 

Seger’s Cones after Firing. 



53 

17. 

Receptacles for Seger’s Cones. 

- 

- 

54 

18. 

Siemens Electrical Pyrometer in use .... 

- 

- 

55 

19. 

Differential Galvanometer. 

• 

- 

56 

20. 

D’Arsonval Galvanometer ------ 



57 

21. 

The Fery Radiation Pyrometer. 

- 

- 

60 

22. 

The Sarco Automatic C 0 2 Recorder—General View 

- 

- 

63 

23- 

Sectional View of the Sarco Automatic C 0 2 Recorder 

- 

- 

64 

24. 

The Simmance & Abady Automatic C 0 2 and Draught Recorder 

- 

67 

25 - 

Apparatus for Distilling a Sample of Tar 

- 

- 

81 

26. 

Special Specific Gravity Bottle for Tar - 

- 

- 

85 

27. 

Hochst Test for Anthracene ------ 

- 

- 

87 

28. 

Apparatus for Estimation of Sulphur in Benzol 

- 

- 

89 

29. 

Apparatus for Estimation of Ammonia - 

- 

- 

90 

30. 

Scheibler’s Calcimeter. 



103 

3 i- 

Schrotter Apparatus. 

- 

- 

104 

32. 

Apparatus for Determining the C 0 2 ... - 

- 

- 

105 







xiv 


LIST OF ILLUSTRATIONS. 


FIG. PAGE 

33. Twaddell’s Hydrometer.- - - - 116 

34. Apparatus for the Estimation of Ammonia - - - - - 119 

35. Apparatus for Dissolving Iron Ores.14 2 

36. Cylinder for Oxide or Weldon Mud Foulings ----- 146 

37. Chart showing Sulphur (Dry Basis) Absorbed by Oxide - - - 147 

38. Colman and Smith Naphthalene Apparatus.152 

39. Chart showing Sulphur (Dry Basis) Absorbed by Weldon Mud - 173 

40. Apparatus for Estimation of Sulphur in Spent Oxide or Weldon Mud 175 

41. Soxhlet Apparatus for the Estimation of Sulphur in Spent Oxide or 

Weldon Mud - - - - - - - - - -176 

42. Methven Screen.178 

43. Graduated Bar with Carriage.- - 179 

44. Bunsen Reversible Disc Box with Mirrors.180 

45. 60-inch Letheby-Bunsen Photometer - - - - - - 181 

46. Candle Balance.- - - 182 

47. Sighting Wheels for Simmance-Abady’s “ Flicker ” Photometer - 187 

48. Simmance-Abady “ Flicker ” Photometer Head - - - - 188 

49. Diagram.192 

50. Simmance-Abady Gas Calorimeter - - - - - - - 198 

51. Do. do. do. —Sectional Elevation - - - 199 

52. Improved Biinte Burette.212 

53. Biinte Burettes and Stand.214 

54. Cooling Jar.. 215 

55. Letheby Specific Gravity Globe.- - 219 

56. Schilling’s Specific Gravity Diffusion Test ----- 220 

57. F. Lux Gas Balance.- 221 

58. Simmance-Abady Specific Gravity Bell ------ 222 

59. Specific Gravity Bottle.226 

60. Specific Gravity Hydrometer.- - 226 

61. Abel Flash-Point Apparatus.227 

62. Pensky-Marten Flash-Point Apparatus.228 


Colour Plate, showing Oxidation Action of Potassium 
Dichromate. facing 


143 




ILLUSTRATIONS IN APPENDIX A. 


PAGE 

1. Harcourt Ten-Candle Lamp.252 

2. Do. do. do..253 

3. Table Photometer - ------- 257 

4. Regulating Tap.258 

5. Sliding Foot of Gas Burner -------- 259 

6. Connecting Rod and Photometric Scale.260 

















LIST OF ILLUSTRATIONS. XV 


FIG. 

7. Adjustable Index. 

8. Clamp and Swivel of Levelling Screw of Lamp 

9. Photoped. 

10. Metropolitan Argand Burner No. 2 

11. Aerorthometer. 

12. Sulphuretted Hydrogen Apparatus - 

13. Apparatus for Sulphur Test - 

14. Boys’ Calorimeter. 

15. Overflow Funnel. 

16. Graduated Measuring Vessel - 

17. Reading Lenses and Pointers - 

18. Change-Over Funnel. 

19. Street Lamp Pressure Gauge - 

20. One-Twelfth of a Cubic Foot Measure - 


PAGE 
26l 
26 2 
263 
266 
268 
272 
273 

275 

276 

277 

278 
278 
280 
282 

























THE CHEMISTRY OF GAS 
MANUFACTURE. 


CHAPTER I. 

PREPARATION OF STANDARD SOLUTIONS. 

The most important part in analytical chemistry is the 
“ making up ” and the standardising of standard solutions. 
The most generally used of standard solutions are given 
here, and how to make them. Their method of use is 
explained in their respective places. 

In analytical volumetric chemistry standard solutions 
are designated normal solutions, when they are of such a 
strength that I litre contains a weight of the reagent 
in grams equal to the chemical equivalent of that reagent; 
thus normal caustic soda contains 40 grams of NaOH per 
litre. The letter N is employed to denote standard normal 
solutions. 

5N = 5 times the normal strength. 

— = one-tenth the normal strength. 

10 

&c. &c. 

The following table gives the combining weight of a 
few of the most frequent reagents used in volumetric 
analysis:— 




2 


PREPARATION OF STANDARD SOLUTIONS. 


Name of Reagent. 

Symbol. 

Molecular 

Weight. 

Combining 
Weight or 
Hydrogen 
Equivalent. 

Ammonia - - - 

nh 3 

17.0 

17.O 

Barium hydrate - 

BaO, H 2 0 

171.0 

85-5 

,, carbonate 

BaC 0 3 

197.0 

98.5 

Calcium hydrate - 

CaO, II oO 

74.O 

37 -o 

,, oxide 

CaO' 

56.O 

28.0 

,, carbonate 

CaC 0 3 

100.0 

50.0 

Iodine - - - 

I 

127.0 

127.0 

Potassium hydrate - ! 

KHO 

56.0 

56.0 

Sodium hydrate - - 

NaOH 

40.0 

40.0 

Hydrochloric acid 

HC 1 

36.5 

36.5 

Nitric acid - 

HNOg 

63.0 

63.0 

Oxalic acid - 

H 2 C 2 0 4 2 lI „0 

126.0 

63.0 

Sulphuric acid 

HoS 0 4 ' 

98.0 

49 0 


It will be observed from the above table that in the 
case of univalent substances, such as ammonia, iodine, 
sodium hydrate, &c., the equivalent and the atomic (or 
molecular, in case of salts) weight are the same, and in the 
case of bivalent substances, such as barium hydrate, barium 
carbonate, &c., the equivalent weight is one-half of the 
atomic weight (or molecular), and in the case of trivalent 
substances the equivalent weight would be one-third of the 
atomic weight. 


Indicators used in Volumetric Analysis. 

Cochineal Solution .—This indicator is prepared by digest¬ 
ing a certain quantity of the powdered or bruised cochineal 
for several hours at a gentle heat in a solution of weak 
spirit, composed of 200 c.c. of methylated spirit and 600 
c.c. of water. The substance is allowed to settle, and 
when clear it is decanted or filtered off, and is then ready 
for use. 

Its normal colour is yellow, and this is changed to a 
reddish violet by alkalies; this reddish-violet colour is 
changed to yellow by mineral acid. But this reaction is 
slower in the case of weak organic acid. It should not 









INDICATORS. 3 

be used in the presence of compounds of iron, aluminium, 
or acetate. 

It is usually adopted for estimation of ammonia in the 
Referee’s test, or in the estimation of ammonia in gas 
liquor and sulphate. This indicator is not affected by C 0 2 . 

Methyl Orange .—This indicator is prepared by dis¬ 
solving some solid methyl orange in a small quantity of 
methylated spirit and diluting with water. 

Methyl orange is employed for the estimation of free 
ammonia in gas liquor. 

Methyl orange is unaffected by C 0 2 , and is specially 
adapted for the titration of alkaline carbonates with mineral 
acid or vice versa. 

Phenolphthalein .—This indicator is prepared by dis¬ 
solving a little of the solid substance in alcohol. The 
solution is colourless, but on the addition of an alkali it 
becomes a deep red colour. The colour is immediately 
changed when the liquid is acidified either with mineral or 
organic acid. 

It cannot be employed in cases where carbonic acid is 
evolved, as carbonic acid destroys the colour, but as the 
bicarbonates (or acid carbonates) do not give the red colour 
with this compound, it is most valuable in indicating the 
first stage in the neutralisation of a normal carbonate, viz., 
the conversion of the normal into the acid carbonate. 
Phenolphthalein is not used in presence of ammonia. 

Litmus Solution .—The solid litmus is boiled with hot 
water; filter, and add a slight excess of acetic acid. The 
solution is evaporated until it becomes pasty, when an excess 
of methylated spirit is added. The spirit precipitates the 
blue colouring matter; the red colouring matter, together 
with the alkaline acetates, remains in solution. The blue 
precipitate is filtered and well washed with spirit. The 
pure blue colouring matter thus obtained is dissolved in 
warm water, and the solution is ready for use. As this 
solution loses its colour if not exposed to the air, it is only 
lightly covered so as to exclude dust, &c. A few drops of 


4 


PREPARATION OF STANDARD SOLUTIONS. 


chloroform well shaken up with it will prevent the forma¬ 
tion of mould. 

The solution is turned from blue to red by acid, and 
vice versa by alkalies ; it cannot be used in the presence of 
C 0 2 , unless the liquid is first of all boiled, and all the C 0 2 
eliminated. 

Lacmoid. —This indicator is made by dissolving some of 
the solid in a weak solution of alcohol. It turns from 
brownish yellow to green on excess of alkali. 

Used in Coleman & Smith test for naphthalene. Will 
not act properly in the presence of carbolic acid, which 
masks the point of neutralisation. 

Sodium Carbonate , Na 2 C 0 3 .—53 grams of Na 2 C 0 3 per 
litre = N solution. This salt must be in an absolute state 
of purity, and is prepared by heating the purest sodium 
bicarbonate to a dull red heat for about ten to fifteen 
minutes, or until no further loss of carbon dioxide or water 
takes place. The salt must not be allowed to fuse. It is 
then cooled in a desiccator and weighed. To ensure that 
the decomposition is complete, it is again heated to a dull 
red heat for ten minutes, and after cooling in desiccator, it 
should weigh the same as before. 53 grams of this are now 
weighed out and dissolved in 1 litre of water. 

This solution is used to standardise the acid solution by, 
so it is necessary to take very great care in its preparation. 

Ammonia, NH 4 OH.—The strong solution, sp. gr. .880 = 
20N. This is diluted to any suitable strength that may be 
required. 

Amitionium Oxalate , (NH 4 ) 2 C 2 0 4 , 2 H 2 0 .—80 grams of 
salt in 1 litre of water =N solution. 

Ammonium Sulphate , (NH 4 ) 2 S 0 4 .—66 grams of salt in 
1 litre of water = N solution. 

Ammonium Thiocyanate, NH 4 CyS.—76 grams of salt 
in 1 litre of water = N solution. 

Barium Hydroxide, Ba(HO) 2 , 8 H 2 0 .—31 grams in 1 litre 

of water = — solution. 

5 


STANDARD SOLUTIONS. 5 


Bromine Water , Br.—Obtained by shaking an excess of 

bromine with water until saturated = — solution. 

2 

Calcium Hydroxide ( Lime-Water ), Ca(HO) 2 .—Obtained 
by shaking an excess of quicklime with water until satu- 
N 

rated, filter = — solution (roughly). 

Hydrochloric Acid. —Pure HC 1 is diluted with water 
until sp. gr. of i.io at 60 degrees Fahr. About 166 c.c. of 
acid are diluted to I litre by distilled water = N solution. 
Its exact strength is titrated against soda. 

Potassium Hydroxide , KHO.—56 grams in i litre of 
water = N solution. 

Potassium Dichromate. —4.913 grams in 1 litre of water 
= — solution, previously dried by gentle fusing in a 
porcelain dish. 

1 c.c. = .0056 Fe. 

1 c.c. = .0072 FeO. 

1 c.c. = .0080 Fe 2 0 3 . 

1 c.c. = .0089 Fe 2 0 3 H 2 0 . 

1 c.c. = .0107 Fe 2 0 3 3H 2 0. 

Potassium Permanganate , KMN 0 4 .—3.16 grams in 1 
N 

litre of water = — solution. 

10 

1 c.c. = .0056 Fe. &c. &c. 


Sodium Hydroxide , NaOH.—40 grams in 1 litre of 
water =N solution. 

Sodium Thiosulphate , Na 2 S 2 0 3 . 5 H 2 0 .—24.^ grams per 
N 

litre of water = —solution. 

10 

N 

Iodine , I.—12.7 grams per litre of water = — solution. 

Silver Nitrate, AgN 0 3 .—16.966 grams in 1 litre of water 

= — solution. 

10 


1 c.c. = .01302 KCN grams. 


6 


PREPARATION QF STANDARD SOLUTIONS. 


For the estimation of chlorine in water, 4.79 grams in 

1 litre of water. 

1 c.c. will precipitate 1 milligram of Cl. 

Di-tri-ortho-phosphate .—This is prepared as follows :— 

2 lbs. of hydrogen disodium phosphate are dissolved in 
1 gallon of water, and 21 lbs. of cupric sulphate crystals in 
1.5 gallon of water. These solutions are well mixed and 
the resulting bright blue precipitate washed by decantation 
and then dried in a water bath at about 212 degrees Fahr. 
This material has a great affinity for SH 2 . 


CHAPTER II. 


COAL. 

The word coal carries a large meaning to the gas chemist, 
and in the analysis required on a gasworks, it is not 
general to ascertain the percentage composition, but it is 
necessary and very important to analyse and ascertain the 
various benefits of one class of coal over another. It might 
be just as well to briefly mention the various stages wood 
or fibrous matter undergoes in its decomposition before it 
ultimately becomes coal. 

When woody matter is buried the composition is greatly 
altered, with the liberation of hydrogen, marsh gas, and 
carbonic anhydride. 

The more water there is present the more rapid is this 
decomposition. 

Coal is the resultant product of this decay, under the 
prolonged influence of heat, moisture, and pressure. 

The longer this influence has been at work the harder 
and richer in carbon is the coal. 

Peat is the most recent product, and graphite the oldest 
or most prolonged. 

The Table given here is by Prof. Raphael Meldola, 
F.R.S., and shows the gradual conversion of wood into the 
oldest carbonaceous material, graphite :— 



8 


COAL. 


Name. 

Carbon. 

Hydrogen. 

Oxygen. 

I. Woody fibre (cellulose) 

50.0 

6.0 

44.0 

II. Peat from Dartmoor - 

54.0 

5.2 

28.2 

III. Lignite or brown coal (an im- > 





perfectly carbonised vege- 





tabledepositof more recent 

• 

66 3 

5.6 

22.8 

geological age than true 





coal) - - - - j 





IV. Average bituminous coal 

77.0 

5.0 

II.2 

V. Cannel coal from Wigan 

81.2 

5.6 

7.9 

VI. Anthracite from Wales 

90.1 

3-2 

2.? 

j 


94 to 99-5; 

, the remainder 

VII. Graphite - - - 


being ash. The 

oldest 

1 


carbonaceous material. 


The chief varieties of coal the gas chemist is called upon 
to deal with are as follows :— 

(i.) Peat, which is hardly a coal in the true sense of 
the word, but which may at no distant date be used for 
gas-making purposes. 

It is the first step in the decomposition of cellular fibre, 
and would in time become coal. 

If at any time the price of coal was such as to prohibit 
its use, peat would then be brought into more notice, and 
would certainly be well worth consideration. 

The one great drawback is the amount of water it 
contains, which is about 90 per cent.; after it has been 
stored under cover for some considerable time the water is 
then decreased to about 60 per cent. 

There are various patents on the market for decreasing 
this amount of water, but at present no great headway has 
been made in this country. On the Continent more has 
been done in this matter, and there are some very excellent 
continuous presses, which decrease the amount of water 
to a more reasonable figure. 

In the carbonisation of dried peat the results are 
very similar to coal, giving a good yield of gas of 
from 10,000 to 11,000 cub. ft., and the purified gas test- 

















PEAT CAKING AND NON-CAKING COALS. 9 

ing about sixteen candles on the No. 2 Metropolitan 
Argand. 

The coke, however, is inferior, resembling the peat, and 
the tar and ammoniacal liquor are fair. 

In December 1902 Mr John Miller, F.I.C., in the 
Glasgow Herald , gives some particulars of the peat industry 
on the Continent and in America, and urges that more atten¬ 
tion ought to be given to the peat bogs of Scotland and 
Ireland. He says that from 1 ton of peat there can be 
produced 12,500 cub. ft. of gas free from sulphur, 16 lbs. 
acetic acid, 46 lbs. wood naphtha, 18 lbs. sulphate of 
ammonia, some tar, and 10J lbs. of paraffin wax. 

(2.) The next stage to be considered is lignite or brown 
coal, and this is peat in a more advanced stage of decom¬ 
position. It is not found in very large quantities in 
England and France, but large deposits occur on the 
Continent, and the yield of gas is very inferior. 

(3.) The ordinary coal may be classified in two 
sections:— 

(a.) Caking coals, (b.) Non-caking coals. 

(a.) Caking coals are those that soften or fuse on 
heating, and on the expulsion of the volatile constituents 
leave a coke that has no cellular structure, or in any way 
resembles the shape of the original coal. 

The exact cause of this caking is not known, as coals 
from the same district and of the same composition are 
not characteristic in this action, some caking, others not 
doing so. 

The most obnoxious constituent of most caking coals 
is the sulphur, but this under the new Metropolitan Gas 
Act is not so serious as in the days of sulphur clauses. 

(b.) Non-caking coals , when carbonised so that the 
volatile constituents are expelled, yield a coke which 
retains the original form of the coal, or else crumbles into 
small fragments, and as a fuel it is inferior to the coke 
of the caking coal variety. Non-caking coals do not differ 
much from caking coals in their elementary composition, 


IO 


COAL. 


and the classification depends upon their behaviour on 
carbonising. 

(4.) Cannel coals appear to hold an intermediary 
position between lignite and bituminous gas coals, and 
are richer in carbon, but poorer in oxygen (see Table). 

The coke is obtained in the form of the cannel and is 
practically useless for fuel. It yields a very high quality 
gas, giving about 12,000 cub. ft. per ton of thirty candles 
gas or more. The best named varieties are Lesmahagow, 
Boghead, and Newbattle. The latter is the general class 
of cannel that is used, and its average result is as 
follows:— 


Specific gravity 
Gas per ton at N.T.P. 

Specific gravity of gas - 
Sperm value from 1 ton 
Illuminating power 
Sulphuretted hydrogen (crude 
gas) 

Carbonic acid 

Carbonic oxide (CO) - 
Coke per ton of coal 


1.175 (water = 1,000). 

13,720 cub. ft. 

668 (air = 1,000). 

1,708 lbs. 

35.24 candles. 

1.50 per cent., or 946.00 
grains per 100 cub. ft. 
3.00 per cent., or 2,451 grains 
per 100 cub. ft. 

8.00 per cent. 

1,089.3 lbs., or 9.72 cwt. 


This is a very rich cannel coal. The foul gas contains 
a rather large percentage of impurities. 

The Lesmahagow cannel coal is practically exhausted, 
and very little is found on the market. 

In the analysis required of a gas chemist by the engineer 
and manager, is not so much the percentage composition 
of the coal, but an approximate report on what he may 
expect from it when carbonising on the works. The usual 
report covers the following ground :— 

I. Yield of gas per ton of coal. 

II. Illuminating power. 

III. Coke per ton (total). 

IV. Coke per ton (saleable). 

V. Sperm value. 


EXPERIMENTAL COAL-TESTING PLANT. II 

VI. Carbonic acid (C 0 2 ). 

VII. Sulphuretted hydrogen (SH 2 ). 

VIII. Sulphur in coal. 

IX. Sulphur in coke. 

X. Value of coke as a fuel, percentage of ash, &c. 

The first seven items are carried out on an experi¬ 
mental plant, which is generally a small plant especially 
fitted up for this purpose, and is as follows:— 

Experimental Coal-Testing Plant. —This plant con¬ 
sists of two small cast-iron retorts, 6 ft. in length, 6 in. 
wide, and 3 in. high, with a direct fired setting and damper 
to the flues, so that you are able to work one retort at the 
time, the second one being handy in case the other cracks. 
By means of the dampers one is able to keep the setting 
under perfect control. The retorts generally project a few 
inches from bed in place of the usual mouthpieces, and 
a 3-inch pipe is fitted for an ascension pipe which leads 
to the condensing tubes, which may be attached to an 
adjacent wall, and consist of ten tubes 10 ft. long and 
3 in. in diameter,'with proper screw caps on the top (for 
cleansing out in case of stoppages) and a small valve on 
the bottom for running off the condensed matter, as tar 
and liquid. It is unnecessary to have a washer, and the 
gas passes direct into the purifiers from the condensers. 

The purifiers are two circular boxes, 24 in. diameter 
and 12 in. deep, fitted with three trays, on which the puri¬ 
fying material is spread. 

Under the new gas regulation (see Appendix) it is only 
necessary to purify from sulphuretted hydrogen, the sulphur 
compounds being left in the gas, and the purifying material 
used is bog-ore or oxide of iron. Some lime can be used 
for experimental purposes, if necessary, on a coal which gives 
a very bad result owing to the C 0 2 being left in ; this can 
be removed and the difference in the test reported on. 

The gas from the outlet of purifiers is led direct to the 
experimental holder, which should hold about 20 cub. ft. 


12 


COAL. 


It is advisable to have two holders—one can be filled with 
gas from the retort and then blown into the other by 
means of weights and suitable connections. The gas 
can then be tested without having to wait for the gas to 
mix in the one holder. The gas can then be tested for 
illuminating power, calorific value, &c. &c. While this is 
being done, another charge can be put on, the gas going 
into the first holder. The charge is 2.24 lbs., or the one- 
thousandth part of a ton, and it is desirable to have a 
special weight made, or else take 2.25 lbs. and divide 
result by .995. The apparatus is shown in Fig. 1. 

When the retort is at the desired heat, the charge is 
weighed out and placed in a small scoop made to fit the 
retort. The lid is smeared round with clay or “ pug,” the 
scoop is driven in, reversed, and withdrawn, and the door put 
on at once. It is necessary to put in a preliminary charge, 
to clean the apparatus of all air and previous samples of 
gas. The gas is blown away on the outlet of holder, or 
burnt at the mouthpiece, and directly the holder is around 
shut the cock on the inlet to holder, which must be opened 
directly the lid is put on after the fresh charge. The charge 
will take from thirty to forty minutes to burn off, and, as 
the plant is fitted with pressure gauges, by shutting off the 
inlet to holder the gauge will indicate whether gas is still 
being made. The holder is weighted in the first instance 
so as to give a level gauge at this point. To increase the 
make, increase the heats, and put a small vacuum on the 
retort. 

The holders are connected up to a photometer, either 
a Letheby, or preferably a standard instrument as the 
Harcourt Table photometer. The results are then certainly 
more reliable. 

Instead of wasting time waiting for the gas to mix in 
the one holder, blow into the second holder ; this will save 
time and greatly facilitate the mixing. Another charge of 
the same coal can be put on, and be burning off, leaving 
the experimenter at liberty to test the first charge. 


EXPERIMENTAL COAL-TESTING PLANT. 


13 



Fig. i.—Apparatus used for Experimentally Testing a Sample of Coal. 
















































































































14 


COAL. 


The illuminating power and calorific value is determined 
as per Metropolitan Referees’ Notifications (see Appendix). 

It is necessary to test at least four samples of the same 
coal, and take the average. 

The tar and ammoniacal liquor are allowed to accumu¬ 
late during the four charges, and are then run off from the 
bottom of the condensers, and are run into a trough and the 
average taken. 

The coke is drawn from the retort into an iron tray and 
put on one side to cool; it is not quenched, and when cold 
is weighed and calculated to its amount per ton of coal 
carbonised. 

A small piece from each charge is kept for further 
analysis in the laboratory. 

It is sometimes necessary to ascertain the amount of 
impurities in the crude gas. In this case it is advisable to 
have a special holder, which can be connected up from the 
inlet of purifiers. A charge can be put in the retort as 
before, the gas passing through condensers only and going 
direct into holder. The holder can then be weighted and 
the gas tested for C 0 2 and SH 2 as follows :— 

A series of weighed U tubes filled with soda lime 
(four being sufficient) are connected up to one another by 
means of rubber tubing; this is connected on to three 
Woulfe bottles containing cadmium chloride which has been 
acidified with a few drops of hydrochloric acid, and the gas 
is then passed through these, going through a small experi¬ 
mental meter last—first soda lime, and then the cadmium 
chloride. 

A foot to 2 feet is quite sufficient for a test. The tubes 
are disconnected and weighed ; the increase in weight gives 
the direct amount of carbonic acid in the quantity of gas 
taken ; this is calculated to grains per ioo cub. ft. 

The Woulfe bottles are then washed out, and a little 
bromine water added ; boil to expel excess of bromine, 
acidulate with hydrochloric acid, and add barium chloride; 
filter off the resultant precipitate of barium sulphate, dry 


WORKING DATA EXAMPLE. 


15 


and burn off in a platinum crucible. The weight of BaS 0 4 , 
multiplied by 0.1459, gives SH 2 in quantity of gas taken. 
This can easily be calculated to grains of SH 2 per 100 
cub. ft. 

The working data and calculations for the above test 
are as follows :— 


Working data — 1st Charge. 

Charge 
Gas made 
Temperature - 

Barometer - - - - 

Tabular number 
Coke - 

Calorific value 

Illuminating power on table photometer 
Sperm .... 


2.24 lbs. coal. 
10.9 cub. ft. 

70 degrees. 
30.26. 

.982. 

24 oz. 

610 B.T.U. 
15.80 candles 
corrected. 

591 lbs. per ton. 


These figures are worked out to the make per ton, and 
all four charges are done separately and average taken. 
The sperm value is calculated as follows:— 

I.P. x yield per ton x 120 
5 x 7000 

or I.P. x yield per ton x 0.00343. 

Example — 10.900 yield per ton. 

15-3 


87200 

545 °° 

10900 


17222 

•00343 


51666 

68888 

51666 


590.7146 lbs. sperm per ton. 







1 6 


COAL. 


The other calculations are simple ; the working out of 
illuminating value and calorific value are given in their 
respective places or chapter. 

Example of Estimation of Carbonic Acid (C 0 2 ) and 
Sulphuretted Hydrogen (SH 2 ) :— 

Carbonic Acid. 


Before 

After 

1 st Tube. 
1000.60 
1003.10 

2nd Tube. 

TOIO.80 

IOIO.90 

3rd Tube. 
1018.60 
1018.60 

4th Tube. 

1030.1 grains. 
1030.1 „ 

Increase 

2.50 

9.10 

Nil 

Nil 


Gas passed, 1.20 cub. ft. 
Temperature, 68 degrees. 
Barometer, 30.26. 

Tabular number, 987. 

987)1.200(1.21 corrected gas used. 
987 


.2130 

1974 

•1560 

1.21 cub. ft. has 2.1 grains C 0 2 ; 

.•. 100 cub. ft. have 2.1 x 100^-1.21 = 2.1 

100 


1.21)21000(181 
121 


.990 

968 

= 1818.18 grains C 0 2 per 100 cub. ft. 

Estimation of Sulphuretted Hydrogen (SH 2 ).—Weight of 
BaS 0 4 x 0.1459 = grains of sulphuretted hydrogen per 
100 cub. ft. 









Extracts Analysis of Coals, by Mr James Paterson (from “Lithology of Gas Coals 


ANALYSIS OF COALS 


17 


a 

3 

3 

in 


c 

<u 

u 

<u 

a 


. O in 

: ^ on 

vd o* 


TO 


. o 


00 >-H 

CO rf 
InOO 
• • 

o o 


CO 

in 


Gas 

Purified 
by 1 cvvt. 
of Lime. 

OOO 

OOO 

OOO:: 

#v rs r\ # # 

O *-0 LO 

t-H HH 

O 

O 

0 : 

•-H 

88 

vo to : : : : 

•S *N # « • • 

10 

*-H l-H 

O O O O 

O O O O 

0 0 : : u 0 : : : 

*N*>* • #N#\# • • 

VO vo CO co 

l-H l-H l-H l-H 

Weight 
of Gas 
per ton 
of Coal 
in lbs. of 
Sperm 

moc 0 
rj- r^. 0 *-< r^» 

rood cd rood 
MOOOO roi- 
\D VO LO LOvO 

O Tj" 

O ro 
d 00 

M 00 

LO 

00 C 4 Oncom 

hh LOOO Tt- ^-vo 

rj- J co d c^i 

O h go r^vo 0 
vo vo vo VO vO 

O VO ^to O O COrtO 

O 04 C O O O t^VO 

r^Chi^vdo d" 04 d\ d" 

VO N ion GO iO *-h 

VO uo vo vo CO ^ d" ^pvO 

, • C /3 

o^.S S 

O 00 M 

O 

0 0 

0 0 

vO 00 O O O O 
<0 ^j- 0 O O O 

i-oi O O O O O 

M OO NO O NO O 

Ian 0. 

rt 

> H.S*g 

00 d O ^d^d 

CO ON N 

ro ro co co co 

d vd 

O On 
co 

vd d cd rf c 4 rf 

VO rr OVOO O M 
co co co CO ^ r^- 

VOOJ^fOJOcfi^Ovt 
vo NNNNOC 4 COCO 

CO co CO CO 04 04 COCOCO 

.2 W)*. 

E .5 S 

N N '‘O h vO 

^ ^00 

r^oo 

VO 

Tt“ r-nOO O VOO) 

h w roo r^vo 

VO O COC 4 CONV^O 

04 vovO vo vo 04 von O 

^11 

HH 

vd vd *d Tj- LO 

HH »—( HH HH H-l 

VO vo 

HH HH 

vd ^-vd vo vd k 

l-H HH t—t l-H kH >—1 

vd vo vo id m oi rd edvd 

i-hi-hi-hi-hhhi-hi-hi-hi-h 

Con- 
densa 
tion by 
Bro¬ 
mine. 

OO ^OO 

0 vo : 00 0 
• • . • • 

Tf rj- co ^ 

LO VO 

HH C 4 
• • 
LO T^- 

VO O vO O O vo 

M O N^O N 

d“ d- d - d - vd d" 

VO O O O O 

04 0 : 0 : : : vo 0 
• ••• ••••• 
vo co TO 

Specific 
Gravity 
of Coal. 

^t-VO Tj- 0 ^ 
VO VO ^ovo 00 

04 OJ 

t_H HH HH *—I HH 

M NH 

vnvo 

hH HH 

M vr^co ++ 04 

V-O vo r ct* i-O Tf -00 

C 4 r 4 04 CV 4 c* 04 

HH HH l-H l-H l-H l-H 

^coo n o^i-a \04 

t^CO ON .00 1^00 On 
04040404 : 04 04 04 04 

l-H HH l-H l-H hh HH l-H l-H 

•fs 

G t^OO ^ O N 

S covo M ^ 

OO O 

00 

O N N O OvLO 
N fO v^ ro N C 4 

vtwON 0400^0 

Tf co N 0 co vo 0 CN co 

< U 

CJ • • • • • 

:• COw COLON 

Cl 

J rf 

O H H H O td 

oi n- d- vd d- d- 04 d vd 

Coke 
per ton. 

00 CO h N O 
tflVO VO w X O 

2 ro Tf M 

tv f\ rv «n «\ 

|_H »—( •—( >—( HH 

0 0 

CO 01 

Tf ^0 

l-H ►—< 

hvO n O M O 

CO co 0 00 vo 

^O CO ^ G" vo 

«\ f\ r\ «\ «\ *\ 

l-H l-H l-H l-H HH l-H 

00 00 VO 00 vo O O 04 vo 
vDVOOOIO^OhO 

CO CO CO Tj- CO CO Tf co 

Art«\nrir.r\nf\ 

hhfhi-h^hhhhhi-hi-hi-h 



O 

O O 

O 

O 

O 

O 

O O 

O 

O O 

O 

O O 

vo O 

O O vo O O 

D 

0 • 

VO vo 04 

O 

O 

O 

O 

O O 

00 

VO O 

O 

vo O 

04 O 

Tf N iO O 

C 

ro A 

04 

O 

VO Tt“ 

VO 

NT 

CO vo 

HH 

CO vovO 

in ov ^roo 

O ^ CO IN 04 

'Ja vj 

rt ■*-» 

•N 

1—1 

04 i-i 

O 

04 

04 " 

o' 

cd of 

of 

04 hh 

HH 

04 0 

O O 

#N ^ #N #N 

O O O CN 04 

O 

HH 

l-H l-H 

l-H 

1—1 

HH 

HH 

l-H HH 

HH 

HH l-H 

HH 

HH HH 

HH HH 

HH HH HH 


cj 

Ih 

w 

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Illuminating power by No. 1 Metropolitan burner. 































i8 


COAL. 


Extracts Analysis of Coals, from Mr James Paterson 
(“Lithology of Gas Coal'’). 


Description of Coal. 

Specific 

Gravity. 

Carbon. 

Hydrogen. 

Nitrogen. 

Sulphur. 

Oxygen. 

JC 

< 

Water Evaporated in 
Pounds from 212 0 F. 
by 1 lb. of fuel. 

Admi¬ 

ralty 

Test. 

Theo¬ 

retical 

Value. 

Calori- 

metrical 

Test. 

Wigan Coal & IronCo. — 
Arley 

Lindsey Arley 

Haigh, yard - 
,, 5 feet - 

Blackley little delph - 
Blackbrook ,, 

Rushy Park mine 
Blackbrook, Rushy Park 
Laffack, Rushy Park - 
Wigan cannel - 

1.260 

1.260 

1.280 

1.260 

1.260 

1.260 

1.280 

1.270 

i -35 

1.23 

83-54 

83.90 

82.26 

74.21 

82.01 

82.70 

77.76 

8l. l6 

80.47 

79-23 

5-24 

5.66 

5-47 

5-03 

5-55 

5-55 

5-23 

5-99 

5-72 

6.08 

O.98 
I.40 
1.25 
0.77 
1.68 
1.48 
1.32 
i -35 
1.27 
1.18 

1-05 

I,5 o 

1.48 

2.09 

1.43 

1.07 
1.01 
1.62 
i -39 
i -43 

5.87 

5-53 

5- 6 4 

8.69 

5.28 

4.89 

8.99 

7.20 

8-33 

7.24 

3-32 

2.00 

3 - 90 
9.21 

4 - 05 

4 - 31 

5 - 6 9 
2.68 
2.82 
4 - 8-1 

8.83 

7-44 

7.90 

7.21 

8.81 

8.29 

8.08 

8.02 

7.98 

7.70 

15-47 

I 5-38 

15-47 

13 - 77 
l 5 - 5 ° 
i 5- 6 3 

14 - 35 

1 5 - 5 i 
15-19 

15.30 

15.00 

15-95 

14-54 

13.20 

13.20 
14.12 
14.12 
14.12 
12.10 


These figures are given to show the working methods, 
and how the results are obtained. 

In these reports it is absolutely necessary to have a 
standard coal, either of some coal which has been worked 
in the retort house, and which one knows will give certain 
results ; this coal can then be used on the experimental 
plant, and its result compared with the special coal under 
analysis. In this way one may have an absolute standard 
coal to go on, and you can give an absolute reliable opinion 
on any coal as to how it will behave under working 
conditions. 

There have been a good many objections to the small 
results obtained on an experimental set, but if these coals 
are compared with any coal of which its characteristics are 
known, these objections fall to the ground. 

In drawing out the report it is necessary to include this 
standard coal in the report, and give the result obtained in 
the experimental set and its result in the retort house. 
The engineer is then able to thoroughly understand the test, 
and due appreciation is given. 























COKE AS FUEL. 


19 


It is also necessary to use the same coke as fuel right 
through the test, and it is only by great attention to details 
that one arrives at a result which will be in any way con¬ 
firmatory with the working result. If this attention is given 
there is not any reason on earth why the results obtained 
should not be trustworthy, and a great guide to the proper 
working of a coal. 

The tabulated copy of a report on a coal is here given, 
and shows how the report is written out. In these ana¬ 
lytical reports on coal there is only one exception that can 
be taken, i.e., the coal is not carbonised by the heat derived 
from its own coke. 

In the retort house, for instance, there is a good coal 
being carbonised which, besides giving a good make, &c., 
gives a coke which is an excellent fuel. Another class of 
coal is brought in which, with the good heats in the setting, 
gives a good make. After a few hours working this coal, and 
when the furnaces have been charged with the coke obtained 
from this coal, the heats begin to drop off, which, on in¬ 
vestigation, is found to be due to the bad quality of the 
coke. This renders the heat in the retort less, and a corre¬ 
sponding drop in the make per ton is noticed. 

This information can be practically gleaned from the 
analytical report if it is properly studied ; for instance, the 
ash in the coke of the standard sample must be compared 
with that in the sample under examination, and also the 
water evaporated per lb. of fuel. It would be as well if 
the chemists drew attention to anything of this sort, so as 
to save the engineer time in going through too many 
details. Special attention should be taken of the ash, as 
if this is high one may expect bad heats, which would be 
due to the increase in the non-combustible matter which 
would clog the furnace and prevent the proper proportion 
of primary air, and would require more labour in “pricking 
up” the furnace to get the utmost efficiency out of this 
coke. 


Report on a Sample of Gas Coal. 


20 


COAL, 








0 

. - . ^ 

: : ; rS 
00 


•pXBpilBJg uo 
aSEtuaDxaj 

IOO.C 





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-odBA^f J3JByV\ 

O 

vO 

HH 





10.20 

0 

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d 

1—1 

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spunoduio^ r, g 

O 

VO 

00 

ro 





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0 

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■vf 

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suibxq 'SB0 

apnx3 ui S HS 

O 

vO 

LO 





0 

d : : : 

d - • • 

CO 

820.0 

UJ "quo ooi xad 
suibxq ’seq 
apiu5 ui s O0 

1200.00 





1600.00 

O 

O 

d 

0 

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HH 

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O 

O 

VO 

LO 





0000 
vd d 00 vo’ 

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ua 

vd 

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CO 

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ui axnisiojA 

a o 

v O 

o 

d r ° 





3.20 

3.20 

•IB03 

ui ajn;sioj\[ 

p. cent. 

2.60 





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o 

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: : : : : 

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: 





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to 

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10.2 





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jo suojpjQ 

HH 

o 

ro 





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VO 





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u-> co u"> 10 

00 

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Suijuutuinpi 

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LO 





O vo O O 
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loirunio 

*—1 b ~1 1 

vO 

tn 

vd 

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aq°3 jo ppiA 

c. q. lb. 

15 O O 





: : : : 

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O 

rt - 

hH 

'd'JL'N , 
<IB°3 jo uox xad 
sbo jo ppiy 

O 

O 

UO 

1—1 





11,100 
11,100 
11,000 
11,200 

11,100 


A 







Description of 
Coal. 

.Standard Coal, ] 
Londonderry. I 

Average of four 1 
charges J 

I. Sample of Coal 
■wider Exa¬ 
mination. 

Oo 

0 

<M vo 
. O 

V s < 

<0 Qj 

1st Charge - 
2nd Charge 

3rd Charge - 
4th Charge- 

Average 


Illuminating power by No. 2 Metropolitan burner. 



















































ANALYSIS OF COAL AND COKE. 


21 


The Analysis of Coal and Coke in the Laboratory. 

After ascertaining the qualities of the coal on the experi¬ 
mental basis it is necessary to examine both the coal and 
coke in the laboratory for moisture, sulphur, &c. These 
methods are as follows :— 

(i.) Moisture. —It is often supposed that to obtain the 
moisture in coal is to weigh out a certain quantity and dry 
it in the water oven ; this is an erroneous method, and 
gives results that are, to say the least, not reliable. It is 
found with this method the coal decreases in weight to a 
certain point, and then increases again. This shows that 
this method is erroneous. The correct and proper method 
is to pass dry gas or air over the coal, and absorb the 
moisture that has been taken out from the coal by the dried 
air or gas in a tube filled with calcium chloride. A large 
cylinder is filled with calcium chloride, and four small U 
tubes with the same material; these latter are weighed and 
the coal is weighed into a dried U tube, and weight taken and 
noted. (Fig. 2.) The method of procedure is:—The gas 
or air is passed through the large cylinder of calcium 
chloride, and then through two of the small U tubes, which 
are weighed before and after the test to ascertain that all 
the moisture is taken out ; the gas then passes through the 
tube which contains the coal, and which is suspended in 
a beaker of boiling water; on the outlet of this tube is the 
other two weighed U tubes, which absorb the moisture in 
the gas which has been taken up from the coal. 

The gas is burnt on the outlet, and the test is kept going 
for two to three hours, when it is disconnected, and the 
tubes on the outlet weighed ; they are again replaced and 
the test continued for half an hour. If the weight of the 
tube is constant the test is finished, but if there is any great 
increase in weight between the first and second weighing, 
they must again be replaced for another half hour. Deduct 
the weight of the tubes from their original weight, and this 
gives the weight of moisture in the coal taken. From this 


COAL. 


22 

the percentage is easily calculated. The third tube must 
not increase in weight at all, if so, it is doubtful if all the 
moisture has been absorbed. 

The tubes on inlet likewise must remain constant in 
weight to be sure that no moisture is going into the coal. 

If the tube with the coal in it is now weighed it will be 
found to have lost more in weight than the calcium chloride 
tubes have gained, showing that any method of drying 



coal and weighing the decrease in weight of the coal is 
obviously inaccurate. 

For moisture in coke this is an excellent apparatus, but 
coke may be safely dried in the water oven. Without any 
error occurring, the loss of weight in coke would be solely 
due to moisture, as coke has already been subjected to a 
far higher degree of heat than it would obtain in the water 
bath. 












































SULPHUR IN COAL. 


23 


Another excellent method is to dry the coal in a 
desiccator over sulphuric acid until the weight is constant. 
This method also only gives the free moisture. (Fig. 3.) 

(2.) Sulphur in coal or coke is best determined by one 
of the following two methods. There are many and various 
methods, but these are undoubtedly the best. 

(#.) Nakamura .—A small but average sample of the 
coal is ground in an agate until the whole will pass through 
muslin or a very fine mesh sieve. Most errors are caused 
through not grinding fine enough. 

One gram is taken and mixed with about five times its 
weight of the following mixture:—13 
parts of anhydrous potassium carbonate 
and 10 parts of anhydrous soda car¬ 
bonate ; this is well mixed with the 
coal and put into a large platinum 
crucible, and some of the mixture (with¬ 
out coal) is sprinkled on the top of the 
crucible. The crucible is then covered 
and the whole gently heated by the aid 
of a spirit lamp for two hours, and no 
smoke must escape from the crucible. 

The heat is gradually increased, and 
the contents should gradually fade to 
a greyish colour. The heat is then increased to redness 
for from one to one and a half hour, and the whole mass 
is then extracted with water, filtered, and bromine water 
added to oxidise sulphides to sulphates; boil to expel 
excess of bromine, acidulate with hydrochloric acid, 
and precipitate the sulphur by addition of barium 
chloride in excess as barium sulphate. Dry, burn off in 
a platinum crucible, and the weight of barium sulphate 
found x 0.1373 X 100 gives the percentage of sulphur in 
the sample. The process depends upon the slow but 
perfect oxidation of the whole of the organic matter 
of the coal, and if any fumes are seen coming from 



Fig. 3. — Desiccator 
used for Estima¬ 
tion of Moisture 
in Coal. 




24 


COAL. 


the crucible the test is worthless, as it shows imperfect 
oxidation. 

(b.) Modification of Eschka’s Process .—One gram of 
finely powdered coal (as before) is thoroughly mixed with 
i gram of light porous magnesium oxide and 0.5 gram of 
anhydrous sodium carbonate in a platinum crucible. 

The crucible is very gradually heated by means of a 
spirit lamp, stirring the mass constantly until strong 
glowing has ceased. The temperature is then gradually 
increased until in about fifteen minutes the bottom of the 
crucible is of a dull red heat. After all the carbon has 
burnt away the mass is transferred to a beaker and 
dissolved in water. The liquid is then oxidised with 
bromine water; filter and wash filtrate, acidulate filtrate 
with hydrochloric acid, add barium chloride, and proceed 
as before. 

These two methods are both suitable for the sulphur in 
the coke. 

The difference between the sulphur in coal and the 
sulphur in the coke is the volatile sulphur, and special 
notice should be drawn to this in making the report on a 
sample of coal for gas making, as it necessitates extra 
expense in purification. 

(3.) Phosphorus. —Ten grams of coal or coke are 
ignited in a platinum basin until only the ash is left; 
this is then fused and digested in a covered beaker with 
20 c.c. of brominised hydrochloric acid for an hour at 
nearly boiling temperature. The bulk of the acid is then 
removed by evaporation, and the solution is diluted with 
30 c.c. of water. The whole is then filtered, and the 
residue washed with distilled water, 15 c.c. of strong 
ammonia are added, and this is neutralised by nitric acid 
from a burette. When re-solution takes place, diluted 
ammonia is added drop by drop until a faint cloudiness 
or opalescence appears; this is then re-dissolved by addi¬ 
tion of a few drops of nitric acid. 


ASH IN COKE. 


25 


The liquid is kept near the boiling point during this 
operation. 

To the faintly acid solution 3 c.c. of strong nitric acid 
are added, and then 5 c.c. of a 10 per cent, solution of 
ammonium molybdate is quickly added, the solution being 
briskly stirred. 

After a second or two the yellow ammonium phospho- 
molybdate settles in a granular form. This is then nearly 



Fig. 4.—Muffle Furnace for Estimation of Ash in Coke. 

boiled for five minutes. The precipitate is then filtered off 
on a tared filter paper, washed with a weak solution of 
nitric acid, dried on the water bath and weighed. 

The weight of precipitate x .163 = per cent, of phos¬ 
phorus (Stock method). 

Ash. —Five grams of finely powdered coal or coke are 
weighed in a platinum basin and incinerated in a muffle fur¬ 
nace (Fig. 4) until constant in weight. This usually occupies 




26 


COAL. 


three to four hours. At the end of the third hour, place 
crucible in desiccator to cool, and weigh, then replace in 
muffle for one hour; cool and weigh again. The weight 
should be constant, if not, repeat operation until weight is 
constant. 

Volatile Matter and Fixed Carbon. —It is sometimes 
useful to know these on a small scale. The method is :— 

2 grams of coal arc ignited in a platinum crucible, with 

close fitting lid ; 
heat gently for the 
first few minutes, 
then over a blast, 
taking care that the 
flame does not en¬ 
tirely envelop all the 
crucible, until all com¬ 
bustible gases are 
driven off; cool and 
weigh. It is neces¬ 
sary to always have 

the gas at the same 

height in every test, 
and three determina¬ 
tions must be made 
on the same sample 
and average taken. 
At the best the results 

pig. 5.—Apparatus used for Estimation of . 

Specific Gravity of Coal. are Only approximate. 

Specific Gravity. —The specific gravity of coal is ascer¬ 
tained on the following principle: that when a body is 
weighed, suspended in liquid, its weight is diminished 
by the weight of the liquid displaced. Therefore if the 
body is weighed first in air, and again when immersed in 
water, the difference between the two weights is the weight 
of water displaced by that body, i.e., the volume of water 






































NITROGEN AND ARSENIC. 


27 


which is equal to the volume of the body. (Fig. 5.) Three 
or four pieces of the sample of coal (representative of the 
sample) are selected, about the size of a walnut. These are 
brushed free from dust, and one piece at a time is weighed 
first in air and then in water. The coal is suspended from 
the arm of the balance (of which one pan is removed and 
a special gravity pan used) by a silken thread. The weight 
of this in air is first taken, and a beaker full of water is 
placed under the coal and is nearly filled with water at 
60 degrees Fahr., and the coal (which reaches to about the 
centre of the beaker) is then suspended in the water. It is 
necessary to remove all air bubbles, and the coal is moved 
up and down until such are all liberated. The coal is then 
weighed. 

The specific gravity is then calculated as follows:— 

Weight of coal in air - - 260.0 grams 

Weight of coal in water - - 59.8 „ 

Loss of weight in water - - 200.2 „ 

260.0 

2 00 2 = I,2 9° specific gravity. 

Nitrogen. —The nitrogen in coal is usually determined 
by Kjeldahl’s method. This depends upon the fact that 
many nitrogenous organic compounds, when heated with 
strong sulphuric acid, have their nitrogen converted into 
ammonia, which at once unites with the sulphuric acid, 
forming ammonium sulphate. The amount of ammonia 
in the ammonium sulphate is then determined by distilling 
with caustic potash into a standard sulphuric acid solu¬ 
tion, and the amount of NH 3 estimated; from this the 
nitrogen is calculated. 

Arsenic. —It is sometimes of very great importance to 
know the amount of arsenic in the coke that is being 
supplied for certain technical purposes. The standard and 
official method adopted by the Government laboratory, 



COAL. 


is known as Thorpe’s method (Journal Chein. Soc. y 1903, 
p. 969). 

By a suitable method of testing, the minutest trace of 
arsenic can be easily determined to amounts below one- 
thousandth of a grain per lb. 

The method adopted by Thorpe is fairly rapid in 
execution and distinguishes the amount of arsenic which 
is volatile, and that which is fixed and is left in the ash. 

A piece of hard glass tube, about 60 cm. long, is drawn 
out, and the drawn-out portion is bent into the shape of an 
adapter, as shown in Fig. 6 , A. Ten grams of the finely 
powdered sample of coke is then introduced into the tube, 
so that it occupies the centre of the tube, leaving empty a 
certain space. A convenient method of introducing the 
fuel is to evenly distribute it on a piece of glazed cardboard 
(to prevent the substance adhering to it), which can be 
inserted in the tube and inverted, the coke distributed as 
desired, the cardboard being withdrawn. 

The drawn-out portion is then connected, as shown, 
with the absorption apparatus containing dilute sulphuric 
acid. A convenient form of apparatus being a modification 
of De Koninck absorption bulbs, so that the products of 
combustion are offered a good wetted surface. The hard 
glass tube is placed in an ordinary combustion furnace and 
connected with an oxygen gasholder. 

The burners beneath the empty portion of the tube are 
first lighted, and a rapid current of oxygen kept continually 
passing through the apparatus. The powdered fuel is then 
heated nearest the inlet of the oxygen, and as soon as the 
combustion once starts, very little heat will be required, and 
the coke burns away without the formation of sooty or 
tarry products. 

The whole operation is under perfect control, and 
occupies from two to three hours, depending upon the 
nature of the coke. 

The ash is left in a loose, pulverised form. The arsenic 
in the fuel is then partly in the ash and partly in the liquid 


ARSENIC. 


29 


or the absorption apparatus, and partly in the end of the 
combustion tubing. 

1. To determine the amount of the arsenic retained in 
the ash:— 

The ash is shaken into a small Kjeldahl’s flask of about 
100 c.c. capacity, which is then attached (preferably by 
means of ground glass joints), as shown in Fig. 6, B, to a 
small condenser, connected to a small flask containing 
about 10 c.c. of hydrochloric acid (sp. gr. 1.1). Into the 
flask containing the ash 25 c.c. of hydrochloric acid con¬ 
taining 0.25 c.c. of strong bromine are added through the 
funnel D. 

Fig. A. 



Fig. 6.—Apparatus for Estimating Arsenic in Fuel. 

Fig. A. — A, Hard glass tube; B, Absorption tube. 

Fig. B. — A, Distillation flask ; B, Condenser ; C, Flask for receiving distillate ; 

D, Funnel. 

The glass is then heated and the liquid maintained just 
on the boil for two hours. After it has cooled, add about 
a gram of potassium metabisulphite, and the liquid is 
again heated until all the free bromine disappears. 

The solution is then filtered free from the insoluble 
or suspended silica, and the filtrate is washed with the acid 
contents of the other flask. It is not absolutely necessary 
to remove the silica, but it facilitates the working and 
prevents irregular boiling. The filtered solution is returned 
to the distilling flask and connected to the condenser, and 
is boiled to expel the sulphurous acid. 












30 


COAL. 


The condenser is then reversed and the liquid distilled 
into the small flask attached to the other end. 

The distillation is continued until the residue in the dis¬ 
tilling flask becomes syrupy, when io c.c. more of hydro¬ 
chloric acid are added to the residue, and the distillation is 
again carried on. 

The total distillate is made up to ioo c.c., and an aliquot 
part of this is transferred to a small porcelain dish, 5 c.c. of 
pure nitric acid and 2 c.c. of pure concentrated sulphuric 
acid are added, and the solution is evaporated until fumes 
of sulphuric acid are freely evolved. 

The dish is cooled and diluted with 20 c.c. of water and 
transferred to a small flask. 

Half a gram of potassium metabisulphite is added, and 
the solution boiled until free from sulphurous acid. 

When cool this solution is ready for the determination 
of the fixed arsenic by means of Marsh’s apparatus. 

2. The amount of volatile arsenic in the combustion of 
the fuel is carried out as follows :— 

The acid in the absorption tube is poured into a small 
beaker, and the absorption tube rinsed with a small quantity 
of water. 

The end of the hard glass tube is then well washed by 
repeatedly sucking the liquid up from the small beaker 
into it. 

Finally the glass tube is washed out with a little more 
acid, and the total washings made up to about 50 c.c. ; of 
this, 25 c.c. are taken and used directly for the estimation of 
the arsenic. The estimation of the arsenic in both solutions, 
or the fixed and the volatile arsenic (which are done separ¬ 
ately), may be made by means of Marsh’s apparatus, and in 
this case it is unnecessary to remove the hydrochloric acid 
by evaporation with nitric and sulphuric acid. 

The nascent hydrogen required for Marsh’s process 
(which is unnecessary to describe in detail, and can be found 
in any good text-book on chemical analysis) is conveniently 
prepared by the action of dilute hydrochloric acid on zinc, 


THORPE ARSENIC APPARATUS. 


3 


mixed with clippings of pure electrotype copper in quantity 
to give a steady and fairly rapid stream of the gas. 

The amount of arsenic obtained is estimated by com¬ 
parison with arsenic deposits obtained from the use of 
arsenious oxide on the same apparatus. 

It is hardly necessary to impress the necessity of carry¬ 
ing out blank experiments on the chemicals and re¬ 
agents to ascertain that they are absolutely free from 
arsenic. 

Thorpe has proposed and used an electrolytic method 
in the place of Marsh’s apparatus. Briefly this apparatus 
consists of a circular glass vessel, provided with a ground 
glass stopper and connections, and carries a drying tube, 
filled with calcium chloride. This with a porous vessel 
forms the inner cell for the cathode where the hydrogen 
and hydrogen arsenide are produced on passing the electric 
current. 

The vessel is opened at the top, and has, passing through 
the ground glass stopper, a tap funnel, the stem of which 
reaches to a point just below the neck of the vessel. From 
the stopper a bent glass tube, bulb shaped, passes off and 
is connected by means of a ground glass joint with the 
drying tube. A stout platinum wire, fused through the 
glass cap, establishes connection between the current 
generator outside and the electrode within the vessel. 

A small Bunsen circular burner is used with this 
apparatus. 

The standard deposits are made from definite strength 
solution of pure resublimed arsenious oxide, which is ground 
to a powder and dried at 100 degrees Cent.; o.i gram is accu¬ 
rately weighed and transferred to a litre flask, but washing 
it down into the flask with i to 2 c.c. of pure hydrochloric 
acid. The liquid must not be heated, and when the solution 
is complete, it is made up to a litre with distilled water. 
Each c.c. of this solution contains o.oooi gram of arsenious 
oxide. 

ioo c.c, of this solution are now accurately measured 


32 


COM 


and diluted to 1,000 c.c. by distilled water. Each c.c. of 
this solution contains o.ooooi gram of arsenious oxide. 

5 c.c. of sulphuric acid are diluted with 20 c.c. of water, 
0.5 gram of potassium metabisulphite is added, and the 
solution is boiled to expel sulphurous acid. When cold the 
solution is tested for its freedom from arsenic. 

Similar quantities of sulphuric acid are now taken, and 
to them in turn arc added varyingquantitics of the standard 
arsenic solutions. 

These are now tested for arsenic deposits, which are the 
standard deposits, and arc tabulated and kept for reference. 



Fig. 7.—Lewis Thompson's Fuel Calorimeter. 


A, Pestle and Mortar; B, Sieve for sifting coal; C, Rough scales; D, Pox containing 
combustion mixture ; E, Cylinders for holding coal and combustion mixture; /<’, Stand 
with clips for holding cylinders; G, Cover to go over//' 1 ; //, Water cylinder; /, 
Thermometer; A', Wire for cleaning G after combustion ; L , Spatula. 


The solutions obtained from the fuel to be tested arc 
next tried for their amount of arsenic, and their deposits 
compared with the standard ones. 

The Calorific Value of Coke.—There arc many appa¬ 
ratus for the estimation of the calorific value of the coke, 
amongst the best known being the Lewis Thompson’s 
calorimeter, Mahler bomb calorimeter, and various modifi¬ 
cations of these. 

The Lewis Thompson calorimeter consists of a cylindri- 








LEWIS THOMPSON CALORIMETER. 


33 


cal copper furnace, a spring clutch base to carry a furnace, 
copper combustion cylinder or furnace fitting the spring 
of the base, a delicate thermometer, clearing wire, and 
graduated glass cylinder, and the oxygen mixture. 

A representative sample is powdered so that it will pass 
through the sieve, and a smaller quantity is then ground to 
a very fine powder in an agate mortar. Two grams of this 
are thoroughly mixed with about ten times their weight of 
the oxygen mixture, which must also be of a fine powder 
and dry. The whole of the mixture is then placed in 
one of the copper furnaces and compressed clown a little 
at a time. 

The furnace is then placed in the socket of the brass 
plate. Place half an inch of fuse on the top, add a little 
oxygen mixture loosely around fuse. The measure is then 
filled with water to the desired mark, which holds 1,934 
grams of water, and its exact temperature noted. If left to 
stand in the round some time it will be the same tempera¬ 
ture as the room. Not more than 2 degrees is the difference 
between the air of the room and the water. Close stop¬ 
cock in combustion cylinder, light fuse, and quickly place 
the cylinder over brass base and furnace, and at once sub¬ 
merge the whole into the glass cylinder of water. 

Combustion will have ceased as soon as bubbles stop 
rising from bottom of cylinder, usually in about a minute, 
open stop-cock, and move cylinder up and down in the 
water so as to equalise temperature. If the condenser 
does not vent when tap is opened, clear passage with 
wire. 

The thermometer is in the water during the whole of 
the operation. 

The difference in the temperature of water before and 
after -f 10 per cent, of the difference (for the heat ab¬ 
sorbed by the metal cylinder). Multiply total difference 
by 1.8 equals lbs. of water evaporated per lb. of fuel. 

To find calorific value multiply total difference in 
temperature by 956 = calories per lb. of fuel. 

C 


34 


COAL. 


Increase = 5.6° Cent. 
10 per cent. = .5 

6.1 


6.1 x 1.8 = 10.98 per lb. 

6.1 x 956 = 5,831.6 calories. 


5,831.6 x 1.8= 10,596.88 B.T.U. 
per lb. 


One of the best modifications of Mahler bomb is that 
known as the Mahler-Donkin bomb calorimeter. 

The bomb in which combustion takes place is made of 
special metal, which resists corrosion and has a very high 
tensile strength. It is plated inside to withstand corrosion 
by the acid generated during combustion. It is fitted with 
a cover which fastens down. This cover has a screw valve 
attached to it to regulate the introduction of oxygen from 
a Brin’s cylinder. The fuel is placed in a platinum crucible 
inside the bomb. 

The electrodes are connected by a fine wire which 
serves to ignite the fuel, and are connected to a battery for 
this purpose. 

One of the electrodes is insulated by a porcelain collar 
where it passes through the cover of the bomb. 

The bomb is placed inside a vessel containing a known 
weight of water, which is stirred by an arrangement of 
paddles to ensure a uniform temperature. This vessel is 
in the interior of an annular vessel, which acts as a water 
jacket. There is also an air space between the inner 
vessel and the water jacket, which serves as a heat insu¬ 
lator, while the outer water jacket prevents heat reaching 
the calorimeter from external sources. 

A thermometer is provided for taking the temperature 
necessary. 

A certain amount of the fuel to be tested is ground to a 
very fine powder, and 1 gram is weighed out and placed in 
the platinum crucible. 

The electrodes are now connected by means of platinum 
wire about 0.1 mgr. in diameter. The loop of the wire 
between electrodes should rest on the fuel in the crucible. 

The bomb cover is now screwed down on a joint of fine 
lead wire. 


MAULER-DONKIN BOMB CALORIMETER. 35 

The cylinder of compressed oxygen is now connected 
to the lower branch provided on the screw valve. 

Connect up pressure gauge, open the valve on bomb 
cover, and then slightly open the valve of oxygen cylinder. 
Gently open the regulating valve and admit oxygen to 
bomb very slowly, and allow pressure to increase gradually 
by degrees. When the pressure is 25 atmospheres per 



Fig. 8.—Mahler-Donkin Bomr Calorimeter. 


square inch, the supply of oxygen is cut off. This quantity 
is ample for the combustion of 1 gram of fuel. 

Close regulating valve and then screw down the valve 
on bomb cover. 

The oxygen cylinder and tubing may now be discon¬ 
nected. 

Weigh out the required amount of water, which is usually 




















































































36 


COAL. 


from 2,000 to 2,500 grams, and pour into the calorimetric 
vessel. Then place bomb and stirring gear in position 
inside the vessel. The water jacket must be kept filled 
with water, and its temperature must be steady at that of 
the atmosphere. Well agitate water and read thermometer. 

The fuel is now ignited by connecting one wire from 
battery to the insulated terminals, and with the other make 
contact with any part of the bomb cover. Combustion 
immediately starts. 

The temperature is taken every half minute until ther¬ 
mometer begins to fall. 

The maximum temperature is carefully noted. 

The stirring apparatus must be kept at work during the 
whole of the period. 

The formula for calculating the results, with no correc¬ 
tion, and these results are sufficiently accurate for all 
practical purposes :— 

If W = weight of fuel tested in pounds. 

H = calorific value of fuel in B.T.U. per pound. 

Wj = weight of water in calorimetric vessel in pounds. 

W 2 = water equivalent of calorimeter in pounds. 

/ 0 = temp. Fahr. of water in calorimeter before combustion. 
t Y = maximum temp. Fahr. of water in calorimeter after 
combustion. 

Then (W a + W 2 ) x (/j - / 0 ) = heat received by water and instrument. 
WH = heat evolved by combustion of fuel sample. 

Hence H = — —x (/j - / 0 ) in B.T.U. per pound. 



CHAPTER III. 


FURNACES—TESTING AND REGULATION. 

It is not proposed to deal in any way with the construc¬ 
tion of retort furnaces and settings, but only to give the 
best methods of regulating these settings from a practical 
scientific point of view. If proper attention is paid to this 
important point on a gasworks, a considerable saving can 
be made in the fuel used in the furnace, giving a corre¬ 
spondingly larger quantity of coke for sale. There are 
various types of settings in use at the present time. The 
following is a brief description of their characteristics : — 

1. Simple direct coke-fired setting, with open grate. 

2. The generator type of setting where solid fuel is 
gasified, but no means for heating primary or secondary 
air. 

3. The regenerator or recuperative setting in which 
the fuel is gasified as in generator, and in addition the 
waste gases are utilised to heat the supply of secondary 
air, and in some cases the primary air also, thus returning 
to the setting heat which would otherwise be lost. The 
principle of the two latter types of gaseous firing is the 
conversion of the carbon in the coke into carbon mon¬ 
oxide at first, and then by the proper admission of second¬ 
ary air to convert this CO to C 0 2 in the combustion 
chamber. 

In the old type of furnace (open grates) the coke is 
burnt to C 0 2 direct in the furnace, and it is necessary to 
have the retorts as near to this source as possible. 


38 


FURNACES—TESTING AND REGULATION. 


The uncontrolled inrush of cold air, the smallness of the 
furnace necessitating the frequent opening of the door for 



Fig. 9.—Tight Clinkering Door, showing Primary Air Torts. 

recharging and clinkering, the use of cold coke, all combine 
to cause great waste of fuel and labour. 

From the chemist’s point of view very little can be done 
with this type of setting. 








GASEOUS FIRING. 


39 


In modern works, direct fired settings have been 
entirely superseded by the system of gaseous firing, the 
advantages of which are readily understood. 

The large furnaces comparatively seldom require 
clinkering and feeding; the use of hot coke and the ad¬ 
mission of just sufficient air for the necessary combustion 
result in large economies in fuel composition and wear and 
tear. A form of gaseous firing is the generator, and the 
more advanced type is the regenerator. 

The settings have an absolutely tight clinkering door 
through which are cut ports to admit the primary air, 
sufficient to convert the fuel into carbon monoxide. 

The combustible gases pass from the generator into the 
combustion chamber, and it is here that the secondary air 
is admitted, and the final combustion takes place. 

The high temperature flame thus formed circulates 
round the retorts, heating them evenly, and without the 
cutting action so noticeable in the direct fired setting. 

If this secondary air is heated by the waste gases, 
further economies are then obtained, and where this is 
done the setting is termed the regenerator type. In these 
settings the waste gases are conducted through passages 
on their way to the exit or main flue. These passages run 
along the side of the secondary air flue, so that the second¬ 
ary air absorbs a certain amount of the heat from the 
waste gases, and instead of entering the combustion 
chamber cold, it has now attained somewhere about the 
temperature the waste gases are leaving. The secondary 
air travels in a directly opposite direction to the exit 
gases, as shown in the illustration. 

The saving in fuel consumption with this latter type of 
setting is considerable. 

Another advantage of gaseous fired settings is that the 
length of flame in the combustion chamber can be con¬ 
trolled, and a large number of retorts grouped in the oven 
and evenly heated. After this brief glance at the various 
types of settings comes what was originally intended to 


4Q 


FURNACES—TESTING AND REGULATION. 


show, viz., the testing and regulation of these settings from 
a chemist’s point of view. The direct fired setting has been 
previously dealt with and needs no further discussion. It 
is not proposed to go fully into the benefits, &c., of various 
furnaces, but it will be as well to point out here that the 



Fig. io.—Sectional Elevation of Retort Setting. 


highest temperature attainable, theoretically, is about 5,300 
degrees Fahr., from which one has to deduct about 1,200 
degrees Fahr. (being approximately the temperature of 
gases in the exit flue), leaving 4,100 degrees Fahr. used by 
the setting, showing a loss of about 26 per cent. 
















































































GENERATOR SETTING. 


41 


In the generator type of setting we have a good depth 
of fuel, of between 3 ft. 6 in. to 5 ft. The furnace door 
is made air-tight, as far as is practically possible, and is 
only opened for clinkering and pricking up purposes. The 



Fig. 11.—Sectional Elevation of Retort Setting, showing Flues and Passages 


furnace is fed through the sleeve in the top of the producer 
with hot coke direct from the retorts. 

On either side of the generator walls are placed the 
secondary air flues. The function of these flues is to 
abstract as much heat as possible from the waste gases. 
The waste gas flues are under the bottom retorts of the 




































































































































42 


FURNACES—TESTING AND REGULATION 



Fig. i2 .—Showing Dividing Walls for Waste Gas Flue. 





















SECONDARY AIR. 


43 


setting, and are as near as possible to the secondary air 
flues. These flues go down the side of the setting and they 
exit at the bottom into the main flue. 

Every unit of heat abstracted from the waste gases and 
returned to the combustion chamber by increased heat in 
the secondary air is so much gain. To keep down the 
temperature in the producer steam is usually supplied by 
means of a continuous stream of water, which drops or runs 
on to the fire-bars, which are usually V or U shaped. 

The action of the steam formed is to prevent the forma¬ 
tion of clinker at the fire-bars by cooling the bars and fuel 
immediately above them, raising the zone of highest tem¬ 
perature some little distance above the bars, and rendering 
the clinker friable and easily removed without damage to 
fire-bars, and less labour. 

In the regenerator type of setting we have a greater 
depth of incandescent fuel, and consequently a more perfect 
reaction in the producer. By their slow travel alongside of 
the secondary air flues the waste gases become reduced in 
temperature, and should leave the setting at about 500 
degrees Fahr. 

The dividing walls should be as thin as possible, whilst 
at the same time possessing reliable joints. A good example 
is shown in the illustration. To prevent short circuiting as 
much as possible, the flues and passages should be periodi¬ 
cally examined and washed out, where practicable, with a 
good fire-proof cement. 

Should by-passing take place it will probably result in 
insufficient secondary air reaching the combustion chamber, 
and the burning of the producer gas in the waste gas flues, 
instead of in the combustion chamber, causing a hot main 
flue and bad heats in the settings. 

Excessive heat in the main flue, i.e., where it is not 
wanted, means, of course, a waste of fuel. 

Every effort should be made, whilst keeping sufficiently 
high heats on the setting, to prevent the heating flame 
from reaching the main flue. This nicety of adjustment is 


44 


FURNACES—TESTING AND REGULATION. 


arrived at principally by the frequent analysis of the gases 
at various points of the setting, carried out as hereafter 
described. 

Faulty heats can rarely be improved by increasing the 
damper ; they should rather be remedied by proper adjust¬ 
ment of the primary and secondary air, and attention to 
the clinkering and pricking up of the fire. 

Analysis of Furnace Gases and Waste Gas from a 
Regenerator Setting. —The sampling of a gas is no easy 
task, and one must take certain precautions to ascertain 
that the sample is a true and representative one, and feel 
confident that there is nothing amiss in the method 
employed. 

The furnace gases being of a fair temperature (verging 
on 2,000 degrees Fahr.) iron tubes will not do. The most 
suitable is undoubtedly a platinum one, but as this is 
generally out of the question, the next best is a porcelain 
tube. A porcelain tube of about 4 ft. long, with a diameter 
of about 1 in. This is then wrapped round with asbestos, or 
better still is placed inside a brass or iron tube and packed 
with asbestos. It is necessary to have a fire-brick with a 
hole in it to take the tube. The joint is made tight by fire¬ 
clay or “ pug.” 

In taking a sample of gas from the producer, it is 
necessary to have a special iron door which fits on to the 
“ sleeve ” or charging aperture in the producer. The tube 
is put through this, and the whole made tight. The tube 
should then be in the top of the “ horse-shoe ” above the 
coke. 

The aspirator (preferably) of glass, which has a capacity 
of a gallon, is now connected on to the tube, and the water 
in the aspirator run out; the gas from the producer is then 
drawn into the space which is left free by the water, and 
after about three-quarters of the aspirator has run out, the 
aspirator is shut off, and the sample is tested. A similar 
proceeding is gone through with another aspirator and tube 


“ORSAT MUENCKE” APPARATUS. 45 

on the exit gases at the same time , so that one has com¬ 
parison in the results. 

The condition of furnace is noted, such as when last 
cleaned, filled, pricked up, &c. 

These samples are now tested, and undoubtedly one of 
the easiest apparatus for this is the “Orsat Muencke,” or one 
of its many varieties. This apparatus gives very good 
results in non-technical hands, and any workman of average 
intelligence can be worked in to its use. 

The apparatus (Fig. 13) is enclosed in a wooden case, 
with sliding shutters at each 
side, and is handy for trans¬ 
portation from place to place. 

Its greatest advantage is 
that the measuring tube is 
jacketed with water which pre¬ 
vents changes of temperature 
affecting the gas volume. 

The apparatus consists of a 
levelling bottle, the burette and 
four absorbing pipettes or 
bulbs, and the fourway con¬ 
necting tubes. 

The pipettes are filled about 
half-way with the required re¬ 
agent, the first one filled with 
potassium hydrate (KOH), the 
second one with an alkaline (potash) solution of pyro- 
gallic acid, and the third one with cuprous chloride ; the 
fourth is not used for these analyses. To adjust the level 
of the reagents in the pipettes, which should be about 
midway between the top of the pipette and the rubber 
connection :— 

This is attained by opening wide the cock upon the 
connector, the levelling bottle being on the table, and very 
gradually lowering the bottle until the reagent is brought 
to the required level; this operation is carried out for each 



Fig. 13.—“ Orsat Muencke” 
Apparatus. 


































46 


FURNACES—TESTING AND REGULATION. 


pipette. The reagents being thus adjusted, the burette and 
connecting tube are completely filled with water by opening 
the cock and raising the levelling bottle. The apparatus is 
now ready to receive a sample of gas. 

The aspirator is connected on to the inlet of the four¬ 
way piece (all the cocks on the pipettes being shut). The 
levelling bottle is now lower, and a sample of the gas is 
drawn into burette. 

This is manipulated until the reading is exactly iooc.c.; 
this is easily arrived at by lowering or raising the levelling 
bottle. The level of the water in this bottle must be at the 
same level as the water in the burette ; shut inlet cock, and 
take the reading on burettes. The levelling bottle must be 
kept level with zero mark during reading, for if the bottle 
is raised the gas is compressed, and if the bottle is lowered 
it is expanded. 

Determination of Carbon Dioxide (C 0 2 ).—The producer 
gas to be analysed is first passed into the first pipette, which 
contains potassium hydrate and will absorb the carbon di¬ 
oxide, by opening the cock connecting this pipette with the 
main fourway piece and raising the levelling bottle, which 
drives the gas from the burette into this pipette, displacing 
the reagent in the front part of the pipettes, leaving bare 
the capillary tubes, which, being covered with the reagent, 
present a large surface to the gas. The reagent moves 
into the rear arm of the pipette. The levelling bottle is 
raised and lowered two or three times, forcing the gas in 
and out of the pipette, and the reagent brought to its 
original place on the stem of the pipette, cock shut, and 
burettes read. The difference between this and the first 
reading gives the percentage of C 0 2 . To be absolutely 
certain that the C 0 2 is all absorbed the operation is 
repeated. The reading must agree to o.io per cent., or 
else the operation must be repeated until such is the case. 
To ensure a fair amount of accuracy the burette ought to 
be allowed two minutes to drain, or otherwise the readings 
will be too low. 


RESULTS OF PRODUCER AND WASTE GASES. 47 

Determination of Oxygen ( 0 2 ).—The residual gas after 
absorbing the C 0 2 is next passed into the second pipette, 
containing an alkaline solution of pyrogallic acid made by 
dissolving pyrogallic acid in potassium hydrate. 

Proceed as before. The difference in reading gives the 
percentage of 0 2 . 

Determination of Carbon Monoxide (CO).—The residual 
gas after absorbing the 0 2 is passed into the third burette 
containing cuprous chloride. 

Proceed as before. The difference in reading gives the 
percentage of CO. 

Now fill up burette with water, blowing the remainder 
of the gas away, and take a sample of the exit gases and 
analyse that in the same way. 

The analyses one would expect from a good regene¬ 
rative setting are:— 


Producer Gas. 

1 to 2 per cent. 
- nil. 

26.00. 


Waste Gas. 



co 2 

<V 

co 


25 to 27 per cent. 

0.40. 

nil. 


Interpretation of Results. —It is waste of time analys¬ 
ing furnace and waste gases if the results are not properly 
understood. The theory of gaseous firing is to convert 
the carbon in the coke into carbon monoxide (CO), and 
afterwards, and in the right place, to burn this to carbon 
dioxide by proper admission of oxygen in the form 
of air. 

The analysis of an ordinary sample of coke is as 
follows:— 


Carbon 


88.3 


Hydrogen 


0.2 
1.1 


Nitrogen 
Water 
Sulphur 
Ash - 


3-5 

0.4 


100.0 



48 


FURNACES—TESTING AND REGULATION. 


The oxygen exists united with the hydrogen in the 
form of water. 

The accepted calorific value of the various constituents 
are:— 


Carbon 

Carbon 

Carbon monoxide 
Hydrogen - 
Sulphur 


14,500 B.T.Units per lb. to carbon dioxide. 
4,303 „ „ „ monoxide. 

4j37° >> >> dioxide. 


52,000 

3)996 


steam. 

sulphur dioxide. 


It will be seen from the above that the richer the coke 
is in carbon better efficiency can be obtained in the setting 
or furnace. 

When the furnace is charged with coke, the primary air 
issuing under the bars first of all combines with the 
carbon, and forms carbon dioxide :—C-f 0 2 = C 0 2 . 

On further progress through the bed of incandescent 
coke, it takes up more carbon and forms carbon mon¬ 
oxide :—C 0 2 + C = 2CO. 

So it is easily seen that the less C 0 2 that one has in 
the producer gas the more carbon monoxide is available 
for combustion, and it is obvious the aim should be to keep 
the C 0 2 as low as possible in the producer. 

If this is high it shows one of two evils ; either there is 
too much primary air (and consequent direct combustion 
will be noticeable by excessive heat in the producer), or 
this effect may be produced by insufficient depth of fuel for 
the chemical reaction to take place. 

In the analysis of the waste gases, which must show 
that no carbon monoxide is going into the main flue, the 
heat is wanted in the combustion chamber and retorts, and 
it is necessary that sufficient secondary air be admitted to 
burn all the carbon monoxide to carbon dioxide in the 
proper place, and the analysis should show a slight excess 
of between 0.4 to 0.6 per cent, of oxygen in the waste 
gases. There will still be sufficient heat in the waste gases 
to give the desired draught. 


WATKINS’ PATENT HEAT RECORDER. 49 

It is never advisable to control a setting by the use of 
the damper, but rather by the proper adjustment of the 
primary and secondary air inlets. 

The damper should be set so that there is a slight 
piessure in producer, which can be observed through the 
sight plugs or the charging aperture or “sleeve.” Sufficient 
has been said to show the importance of furnace gases 
analyses and the interpretation to be put on them. 

It is often necessary to ascertain the heat in the setting 
and waste gas flues, as it is generally desired to work to as 
high a heat as the material will sustain. 



Section Before Firing. 



Section After Firing. 

Fig. 14.—Watkins’ Patent Heat Recorder. 


There are numerous apparatus on the market for this 
purpose. One of the simplest is Watkins’ patent heat 
recorder, and another of similar type is the Seger cone 
pyrometer. These are both on the same principle, viz., 
the use of various substances, the fusing points of which 
are known, and a series of these are grouped and marked 
so that it is easy to ascertain the temperature by noting 
which one fuses. 

The heat recorder patented by Mr Henry Watkins of 
Burslem (Patent No. 6,288, 1900) consists of rectangular 

D 





50 FURNACES—TESTING AND REGULATION. 


blocks, each having five cylindrical recesses. Each recess 
has a number which denotes (in the table appended thereto) 
the temperature at which the test piece in the recess 
will fuse. 

The cases are numbered consecutively, each case form¬ 
ing a series with a considerable range of temperature. 

The test pieces or pellets are loose in case before 
fusion, and are wrapped in paper to prevent them falling 
out during transit, and the paper should not be removed ; 
this will burn off. 

These test pieces are composed of silicates, and are of 
definite chemical composition, and are tested before being 
sent out. 

The duration of test in all cases is five minutes. The 
method of making a test is by using a bar of iron flattened 
at one end, on which the recorder is placed, and which is 
then placed in the flue or place which is desired to be 
tested. 

In making a test, for example, suppose No. 11 pellet has 
fused, and No. 13 remains intact, the temperature on 
referring to the table will be between the two, viz., 1,634 
degrees Fahr., or between that and the next (No. 13) = 
1,742 degrees Fahr. To ascertain which series of the 
recorder should be used, the ranges of each are given, and 
it may be necessary to try the series below or above, as the 
colour is only approximate :— 

A series - - - Faint red to bright. 

B - - - Bright red to low orange. 



Low orange to bright orange. 
Bright orange to white. 
Dazzling white. 


v 


seger’s cones. 


51 


Series and 

N umbers. 

Temperature. 

Degrees 

Centigrade. 

Degrees 

Fahrenheit. 

A. 1 - 

590 

1,094 

3 - 

650 

1,202 

5 - 

710 

B 3 IO 

7 - 

770 

1,418 

9 - 

830 

1,526 

B. 11 - 

890 

1,634 

13 - 

950 

1,742 

15 - 

990 

1,814 

17 - 

1,030 

1,886 

19 - 

1,070 

1,958 

C. 21 

I,IIO 

2,030 

23 - 

1,150 

2,102 

25 - 

1,190 

2,174 


Series and 
Numbers. 

Temperature. 

Degrees 

Centigrade. 

Degrees 

Fahrenheit. 

C. 27 - 

1,230 

2,246 

29 - 

1,270 

2,318 

D. 31 - 

i, 3 i° 

2,390 

33 ~ 

b 35 o 

2,462 

35 - 

i, 39 o 

2,534 

37 

i, 43 o 

2,606 

39 - 

1,470 

2,687 

E. 41 - 

1,510 

2 , 75 o 

43 - 

i, 55 o 

2,822 

45 - 

1,590 

2,894 

47 - 

1,630 

2,966 

49 - 

1,670 

3,038 


Another method of easily determining the temperature 
of a retort or any part of the setting is by using Seger 
cones. Professor Dr H. Seger and E. Crammer, after 
numerous experiments, employed various earthen silicates, 
moulded into the form of tetrahedra or triangular 
pyramids. By varying the proportions of the ingredients 
in the mixtures forming these pyramids, it is possible to 
vary the temperature at which they melt. Every sub¬ 
stance has a definite melting point, which is always the 
same provided the substance be pure. By adding to it 
another substance, we obtain a mixture which possesses a 
different melting point. By adding yet other substances 
and varying the proportions in which such substances are 
introduced, we can produce resultant mixtures which will 
always melt at definite temperatures. 

These are the facts which have been relied upon, result¬ 
ing in the production of the Seger cones. 

Seger cones have melting points which range from 500 
degrees Cent, to the melting point of platinum. 














52 


FURNACES—TESTING AND REGULATION. 


The following Table shows which cones are most 
adapted for use with various classes of goods :— 

Porcelain colours and lustres, Nos. 022 to 010. 

Goods manufactured from clays and containing a consider¬ 
able amount of lime and iron oxide ( e.g ., stove tiles), 
Nos. 015 to 01. 

Goods manufactured from clays poor in lime and iron, e . g ., 
floor tiles, Nos. 1 to 10. 

Stoneware with salt or loam glaze, Nos. 5 to 10. 

White stoneware, &c. (hard burnt), Nos. 3 to 10. 

White stoneware, &c. (mild burnt), Nos. 010 to 01. 

Cement and porcelain, Nos. 10 to 20. 

Refractory glazes, Nos. 20 to 25. 

For determining the fire-resisting power of refractory earths, 
Nos. 26 to 36. 


Table showing Melting Points of Seger Cones. 


No. of 
Cones. 

Melting 

Point. 

Degrees 

Cent. 

Melting 

Point. 

Degrees 

Fahr. 

No. of 
Cones. 

Melting 

Point. 

Degrees 

Cent. 

Melting 

Point. 

Degrees 

Fahr. 

No. of 
Cones. 

Melting 

Point. 

Degrees 

Cent. 

Melting 

Point. 

Degrees 

Fahr. 

022 

590 

| UO94 i 

02 

1,110 

2,030 j 

19 

L 5 IO 

! 2,750 

| 021 

620 

1,148 | 

OI 

1,130 

2,066 

1 20 

1,530 

2,786 

020 

650 

1,202 

I I 

1,150 

2,102 

21 

1,550 j 

2,822 

OI 9 

680 

I 1,256 

2 

1,170 

2,138 

22 

1,570 

2,858 

Ol8 

710 

| b 3 io 

3 

1,190 

2,174 

23 

1,590 

2,894 j 

i 017 

740 

1,364 

4 

1,210 

2,210 

24 

I,6lO j 

2,930 

! 016 

773 

1,419 

5 

1,230 

2,246 

25 

U630 

2,966 

! °I 5 

800 

1,472 

6 

1,250 

2,282 

26 

1,650 

3,002 

014 

830 

1,526 

7 

1,270 

2,318 

27 

1,670 

3,038 

1 013 

860 

1,580 

| 8 

1,290 

2,354 

28 

1,690 1 

3,074 

012 

890 

1,634 

9 

U3IO 

2,390 

29 

1,710 ! 

3,110 I 

on 

920 

1,688 

10 

J , 33 0 

2,426 

30 

1,730 

3 U 46 ; 

010 

95 ° | 

1,742 

11 

i, 35 o 

2,462 

3 1 

1,750 1 

3,182 

09 

970 

1,778 

! 12 

i, 37 o 

2,498 

32 

1,770 

3,218 ! 

08 

990 

1,814 

*3 

i, 39 o 

2,534 

33 

1,790 

3,254 

07 

1,010 

1,850 

14 

1,410 

2,570 

34 

1,810 

3,290 

06 

1,030 

1,886 

15 

i, 43 o 

2,606 

35 

1,830 1 

3,326 j 

05 

1,050 

1,922 

16 

1,450 

2,642 

3 6 

1,850 

3,362 J 

| 04 

1,070 

1,958 

1 7 

1,470 

2,678 

37 

1,870 | 

3,398 

03 

1,090 

1 

1,994 

18 

1,490 

2,714 

38 

1,890 

3,434 


In order to determine what cones are required when 






























seger’s cones. 


53 


desiring to regulate the burning of any setting or furnace, 
&c., it is necessary for the first few times to place a few 
cones in the setting, or wherever it is, and surround them 
with bricks (Fig. 15) or a muffle, or any arrangement that 
will keep them from being in direct contact with the 
flame, and then observe how 
they behave. If, for example, 
they exhibit the following ap¬ 
pearance (Fig. 16), the conclu¬ 
sion might be drawn that the 
temperature agreed with the 
melting point of cone No. 7, 
because cone No. 6 is com¬ 
pletely melted, whilst cone No. 

7 has bent over so that its apex tends to approach the 
base, and cones Nos. 8 and 9 have remained erect and 
with their edges sharply defined. 

Suppose it were found that on examining the goods that 
the fire was stronger than usual or heat too great, then 



Fig. 15.—Seger’s Cones in use. 



Fig. 16.—Seger’s Cones After Firing. 


after reducing the heat by various means another set of 
cones could be put in, for example, cones Nos. 4, 5, 6, 
and 7, and note what happened here. Supposing No. 
6 was the one whose apex tends to touch the base, 
that would then be the temperature, viz., 1,250 degrees 
Cent, or 2,282 degrees Fahr. The other cone No. 7 





54 


FURNACES—TESTING AND REGULATION. 


could be left in and occasionally observed to see if heat 
increased. 

The cones must always be placed in such a position 
that they are exposed to the full heat, and they do not 
encounter any live flame. The cones can be easily placed 
in the flues where they are protected from direct flame, and 
the heat of the secondary air easily ascertained, also exit 
gases, &c. 

These cones can also be used to ascertain the heat in 
the producer, and can be lowered down into the producer 
through the feeding sleeve, the cones themselves being 



Fig. 17.—Receptacles for Seger’s Cones. 


contained in a fire-clay receptacle which should preferably 
be covered, as, if the cones are touched in the heated state 
by dross or ashes, their melting point will be affected. 
The receptacles most commonly used are such as are 
shown in Fig. 17. 

There are many electrical pyrometers, amongst the best 
being Fery’s radiation pyrometer, and Siemens’ electrical 
pyrometer. 

The Siemens electrical pyrometer is a platinum 

resistance thermometer, of which the essential element is 
a coil of platinum wire wound upon a cylinder of refrac- 

















SIEMENS ELECTRICAL PYROMETER. 55 

tory material, and protected by a long closed tube. For 
measuring the resistance of the coil in order to ascertain 
its temperature, two types of apparatus are made. 



Fig. 18.—Siemens’ Electrical Pyrometer in use. 


The first comprises a differential galvanometer and a 
set of resistance coils, and gives readings in ohms, from 


































56 FURNACES—TESTING AND REGULATION. 


which the temperatures are ascertained by means of a 
special table supplied with the apparatus (Fig. 19). 

The second is a combination of a small D’Arsonval 



Fig. 19.—Differential Galvanometer. 









































































SIEMENS ELECTRICAL PYROMETER. 57 

galvanometer and a Wheatstone bridge of circular form 
with sliding contact, and gives readings directly in Fahren¬ 
heit or Centigrade degrees as desired (Fig. 20). 



Fig. 20.—D’Arsonval Galvanometer. 





























58 FURNACES—TESTING AND REGULATION. 

The pyrometer is most accurate ; its reading can be 
depended upon to within a fraction of i percent. It is also 
very simple in its action and management and its working, 
and may be safely entrusted to the care of an intelligent 
workman. 

The method of connecting up the pyrometer with the 
differential galvanometer is shown in figure. Starting at 
the negative pole of the battery, a lead runs to the terminal 
z of the pyrometer tube, from which a wire extends to one 
end of the platinum resistance wire. At this point the 
circuit divides into two branches. One branch contains a 
wire running straight back to the pyrometer terminal x', 
whence a lead B extends to the measuring apparatus, and 
is connected, through a resistance box and one coil of the 
differential galvanometer, with the positive pole of the 
battery. 

The other branch includes the platinum resistance 
wire, a wire running to the pyrometer terminal X v and a 
lead A extending to the measuring apparatus, where it is 
connected through the second' coil of the differential gal¬ 
vanometer with the positive pole of the cell. When the 
resistances of the two branches are equal, equal currents 
will flow through the coils of the galvanometer when the 
key IC is depressed, and no reflection will be produced. 
The leads A and B from the pyrometer tube to the 
measuring apparatus are made of the same material and 
lie close to each other, so that their resistances are always 
equal, whatever may be their common temperature. The 
two wires within the pyrometer tube are also similar 
in all respects, so that their resistances always remain 
equal. 

Thus it appears that the only independently variable 
resistances in the two branches of the circuit are the 
platinum spiral in one branch, and the resistance box in 
the other ; the resistance unplugged in the box is thus 
equal to that of the platinum spiral when no deflection 
occurs in the galvanometer on depressing the key K. The 


f£ry radiation pyrometer. 


59 


direct reading instrument comprises a Wheatstone’s bridge 
and the necessary leads to the pyrometer tube. 

Starting from the positive pole of the battery, a lead 
extends to the terminals z of the pyrometer tube, whence 
a wire is connected to one end of the platinum resistance 
spiral. This junction forms one angle of the Wheatstone’s 
bridge lozenge (see small diagram). 

From it extends a wire running straight back to the 
pyrometer terminal x v whence a lead extends to an arm 
which makes contact with a helical coil of wire arranged 
round the edge of a circular dial, thus forming one arm of 
the Wheatstone’s bridge. 

The conjugate arm of the bridge contains the platinum 
resistance wire, a wire running to the pyrometer terminal 
X, and a lead which extends back to the apparatus. 

The two remaining arms of the bridge are made up of 
equal and constant resistances, the galvanometer being 
connected up as shown. 

When no deflection is produced in the galvanometer on 
depressing the key, the two variable arms of the bridge 
must have equal resistances, since the resistances of the 
remaining arms are always equal; and since the two 
variable arms comprise equal leads, it follows that the re¬ 
sistance of that part of the helical coil thrown into circuit 
by the contact arm must be equal to the resistance of the 
platinum spiral in the pyrometer tube. 

The Fery Radiation Pyrometer.—This instrument 
was invented by Professor Fery of the Ecole de Physique 
et de Chimie, Paris. It is capable of taking very high 
temperatures, and consists of two adjustable lenses and a 
thermo-couple made of constantan (an alloy of 60 per cent, 
of copper and 40 per cent, of nickel) and copper wires. 

In temperatures where the resistance thermometers 
cannot be supplied, with this pyrometer the height of the 
temperature does not matter, as no part is raised more than 
80 degrees Cent, above the air temperature, and the pyro- 


6 o 


FURNACES—TESTING AND REGULATION. 


meter is not exposed to the action of the flue gases, and it 
is therefore a very valuable instrument in measuring high 
temperatures in the retort house. 

The radiation emerging through a sight hole in the 
furnace is focussed upon the very sensitive thermo-couple, 
which is supported and protected from extraneous rays by 
screens. When the adjustment is correct, the image of the 


D E 




Fig. 21.—The F£ry Radiation Pyrometer. 


observation hole should completely cover the junction. 
The thermo-couple is connected to a Meylan-D’Arsonval 
galvanometer, divided into millivolts and degrees Centigrade 
for direct reading. 

The horseshoe magnet has a single air space, and the 
movable coil of the galvanometer is balanced by the needle 
pointer, which records the direct readings of the tem¬ 
perature. 





























THE WANNER PYROMETER. 


61 


The Wanner Pyrometer.—This instrument serves for 
measuring temperatures from 900 degrees Cent, and up¬ 
wards. This is on similar lines to the Fery, as the tempera¬ 
ture of a glowing body is ascertained by the intensity of light 
it emits. This is according to Wien’s or Planck’s law. 

It is owing to the great increase in the intensity of 
light that even slight changes in temperature—tenths of a 
degree—give rise to perceptible and measurable differences 
of radiation, so that a change in the intensity of light is a 
delicate test respecting change in temperature. 

Taking I to be the observed intensity of the rays, T the 
absolute temperature, A the wave length of the part of the 
spectrum used, c x and c 2 two constants, e the basis of the 
nat. logarithms, the following is the equation which connects 
the value:— 

I = ^ • e (Wien’s formula), 

with an essential limitation to be referred to later on. As there 
is no measure by means of which intensities of light can be 
determined so as to be scientifically correct, one can but com¬ 
pare the intensity of one source of light with that of another. 

Assuming I 0 to be this comparison measure, and T 0 the 
corresponding absolute temperature, it follows, of course:— 




or 


Io 


_£?/J __L\ 
£ \Vt tJ 


If one knows in this equation the value of I 0 and T 0 , 
viz., the standard measures, and, moreover, that of I and c 2) 
there is left only T as an unknown quantity which can be 
ascertained by calculation. 

The aforesaid limitation is as follows :—In point of fact, 
the above-mentioned law applies only to so-called absolutely 
dark bodies. By making a small aperture into the wall, 
the radiation is not affected to a measurable degree; it 
remains, therefore, absolutely dark. 


62 


FURNACES—TESTING AND REGULATION. 


The light observed enters the apparatus through a slit, 
through lenses and a right angle prism ; there results a 
spectrum from which, by means of a screen, light of a definite 
wave length is cut off, and the intensity of the light is 
measured by polarisation. 

The part of the apparatus facing the radiation to be 
measured is fitted with a small 6-volt electric lamp, whose 
light likewise passes through the apparatus and is used by 
way of a standard with regard to the intensity to be 
measured. Looking through the apparatus, one perceives 
the circular field of view divided into two semicircles, one 
of which is illuminated by the small electric lamp ; the other 
is red by the light emitted by the substance to be examined. 
By adjusting a movable eyepiece in which there is a Nicol’s 
prism, the two semicircles of the field in view can easily be 
adjusted to equal intensity. By the aid of the graduated 
circle one reads off the rotation, and by referring to a table 
one ascertains the temperature, which is calculated on the 
basis of the aforesaid law. 

There are one or two very good automatic C 0 2 recorders 
on the market, and amongst the best known are :—(i) The 
“ Sarco,” made by Sanders, Rehders, & Co. Ltd., Fenchurch 
Street, London, E.C.; (2) The Simmance & Abady C 0 2 
and Draught Recorder, by Messrs Alex. Wright & Co., West¬ 
minster. Either apparatus automatically records continu¬ 
ously on a chart, which is changed every twenty-four hours, 
the percentage of CO, 2 in either the boiler flues or waste gas 
flues. Both of these instruments are most suitable for con¬ 
tinuous C 0 2 records in the manufacture of water gas, and 
where such instruments are continually in use they must be 
of benefit, and help the efficient working of the plant. The 
former apparatus is described on pp. 63-66, while the latter 
instrument is illustrated on p. 67, and referred to on p. 68. 

Fig. 22 shows the general view of the “Sarco” C 0 2 
recorder. 

Fig. 23 shows the same instrument, but a sectional 
elevation view. 


THE SARCO AUTOMATIC C 0 2 RECORDER. 63 

A f-in. pipe, which taps the side flue or last combustion 
chamber of the boiler or furnace, is connected to the instru¬ 
ment at 3 (Fig. 23), and in order that the gas samples may 



Fig. 22.—The Sarco Automatic C 0 2 Recorder—General View. 

be secured rapidly and continuously the circuit is com¬ 
pleted by another pipe of the same diameter. This is 














































































































































SARCO C0 2 AUTOMATIC RECORDER. 


65 


connected at 7, and carried to the base of the chimney, or, 
where this is impracticable, to a convenient point in the 
main flue, well beyond the boiler damper. Thus a continu¬ 
ous and rapid passage of the gas is secured, which, in 
average cases, renders it possible to read on the chart the 
effect of an alteration in the firing within two minutes of its 
occurrence. 

The instrument is so sensitive that the slightest change 
is clearly depicted, and its operations are so rapid that 
as many as thirty-five to forty separate analyses can be 
recorded per hour. 

The power required to procure and deal with the gas 
samples is derived from a fine stream of water at a head of 
about 2 feet. Any ordinary clean water may be used, 
only 2-5 gallons are required per hour (according to the 
speed at which the machine is operated), and the water may 
be used again after passing through the recorder. 

It enters the instrument at 8 through the small glass 
injector 9. Of the latter several are provided, having 
apertures of various sizes, and by their use the speed of the 
machine may be adjusted at will. The water now flows 
through 74 into the power vessel 82 ; here it compresses 
the air above the water level, and this pressure is trans¬ 
mitted to vessel 87 through tube 78. The pressure thus 
brought to bear on the surface of the liquid (two parts of 
water to one of glycerine) with which 87 is filled to mark 
95, sends the liquid upwards through tubes 91 and 93. 
Thence it passes up into vessels 77, 66, 67, and 68, and 
into tubes 51, 52, 48, and 49. Here it rises until it reaches 
the zero mark, which will be found on the narrow neck of 
vessel 67. 

At the moment it reaches this mark, the power water, 
which, simultaneously with rising in vessel 74, has also 
travelled upwards in syphon 72, will have reached the top 
of this syphon, which then commences to flow. 

Through this syphon 72 a much larger quantity of 
water is disposed of than flows in through injector 9, sq 

E 


66 


FURNACES—TESTING AND REGULATION. 


that the power vessels 74 and 82 are rapidly emptied 
again. 

The moment the pressure on vessel 87 is released, the 
liquids return from their respective tubes into this vessel. 

Presuming tube 49 to be in connection with a supply 
of flue gas, a sample of this is drawn in from the continu¬ 
ous stream which passes through 43, 45, and 46, as the 
liquid recedes in 49, by the vacuum which is created by the 
falling of the liquid. 

As soon as the liquid has dropped below point 76, 
which is the inlet of the flue gas into vessel 68, the gas 
rushes up into this vessel, and a portion out into the 
atmosphere through outlet 70, tube 48, and seal 80. 

As soon as the flow in the syphon is interrupted, vessel 
82 begins to fill again, and the liquids in tubes 91 and 93 
rise afresh. The gas in 77 and 68 is now forced up into 
tube 50, and caused to bubble right through a solution of 
caustic potash (sp. gr. 1.27) with which vessel 94 is filled 
to mark 64. 

In this process any carbon dioxide (C 0 2 ) that may be 
contained in the gas is eagerly absorbed by the potash. 
As the gas has to pass through the potash, the absorption 
is rapid and complete. 

The remaining portion of the sample collects in 62 and 
passes up through 66 into tubes 57 and 58. (It cannot 
pass out at 59 as this outlet is sealed by the liquid in 52.) 

The gas now passes under the two floats 18 and 26, 
whereof the former is constructed larger and lighter, and 
will therefore be raised first. 

By an adjustment of the thumbscrews 14 and 15 the 
stroke of this float is adjusted until just 20 per cent, of the 
whole of the sample (100 c.cm.) remains to raise float 26, 
when nothing is absorbed by 94. This float has attached 
to it pen 36, which is caused to travel downwards on the 
chart, when 26 rises. If no C 0 2 was contained in the gas 
nothing would be absorbed by the potash in 94, and the 
whole of the 20 per cent, would reach float 26. Thus 



Fig. 24.— The Sjmmance & Abady Automatic C 0 2 and Draught Recorder. 







































































68 


FURNACES—TESTING AND REGULATION. 


the pen would be caused to travel the whole length of the 
chart from the 20 per cent, line at the top to the zero 
line at the bottom. Any C 0 . 2 gas contained in the sample 
would be absorbed by the potash, a correspondingly less 
quantity .would reach float 26, and pen 36 would not travel 
right down to the bottom of the chart, i.e., the zero line. 
Thus any C 0 2 absorbed will be indicated by the tops of 
the lines on the chart. 

On the return stroke of the liquid the gas is drawn out 
from under the floats 18 and 26 through 57 and 58, and 
into tubes 59 and 52. From here it passes out into the 
atmosphere at 66, and through tube 51, as soon as the 
liquid has fallen below the outlet of tube 52. 

It will be seen that the gas, when analysed, leaves the 
recorder by a set of tubes entirely separate from those 
through which the samples are obtained, so that there is no 
possibility of mixing the old with the new. 

The Simmance-Abady Co 2 mbustion Recorder, in addi¬ 
tion to performing the continuous C 0 2 record, also marks 
continuously on the chart either the amount of draught 
in the boiler or main flue, or the difference between the 
draught below the fire and in the boiler flue, and therefore 
furnishes the fireman with an additional guide as to the 
thickness or condition of the fuel bed. It is different in 
construction to the “ Sarco ” apparatus, being entirely with¬ 
out glass parts or rubber tubes, while the motive power is 
a slight dribble of water. The whole apparatus is contained 
in a small iron case. It is an English-made apparatus, and 
is very simple in its construction, while an important point 
in its favour is that it is unaffected by changes in tempera¬ 
ture. It draws the gases whether they are under forced, 
induced, or natural draught, and its record of C0 2 is a 
continuous line. 


CHAPTER IV. 


PRODUCTS OF CARBONISATION. 

Of the products of carbonisation or “destructive distilla¬ 
tion ” the chief one from a gas engineer’s point of view is, 
of course, gas. 

The yield of gas will greatly vary according to the 
temperature of the retort, the class of coal, the quantity 
carbonised, the period of distillation, and numerous other 
factors, known and unknown. The yield of gas per ton of 
coal carbonised, if the temperature is comparatively low, 
would be about 9,500 cub. ft., 11 gallons of tar, a low yield 
of ammonia as well as other bye-products, as cyanogen, 
naphthalene, &c. The average analysis of a gas of this 
kind which had been purified for the elimination of NH 3 , 
C 0 2 , SH 2 , &c., would be :— 


co 2 - 

0.20 

to 

0.5 per cent. 

CO 

5.00 

>> 

7.00 „ 

Methane 

- 37-oo 

}> 

39.00 „ 

Hydrogen 

- 5 1 - 00 

}} 

53 -oo 

Unsat. Hydrocarbons 

- 7 -o 

55 

9.0 


The tar would be richer in its various bye-products, such 
as naphthalene, light oils, phenols, &c. The illuminating 
power would be higher, also the specific gravity and the 
calorific value. 

As the temperature of carbonisation increases, the yield 
of gas increases, the make of tar both in quantity and 
quality drops off, and the illuminating power drops, but 
more ammonia is formed. 


70 


PRODUCTS OF* CARBONISATION. 


The hydrogen increases, likewise the marsh gas or 
methane, but the olefine or unsaturated hydrocarbons will 
be found to have decreased, and the naphthalene will be 
found to have increased. 

When we get the higher heats of the up-to-date and 
present day carbonising, with a yield of gas of over 11,000 
cub. ft. per ton, the gas will necessarily be of a much 
poorer quality, the illuminating power will have decidedly 
decreased to the extent of a candle or two. The make of 
tar will show a corresponding decrease, and that trouble¬ 
some product naphthalene will cause more trouble than ever. 
It is generally known that although the specific gravity of 
the tar increases, the higher the make, the quantity of tar 
is less. The cause of this increase in gravity is due solely 
to the increase in pitch. 

The ammonia, naphtha, and light oils decrease in 
quantity; the creosote, anthracene, &c., in the same 
direction, although in a less marked degree. 

Mr Lewis T. Wright, F.C.S., has carried out some 
valuable experiments in this direction, and he found the 
effect of heat on the yield of quantity of tar is affected to 
a much greater extent than the gas by high heats. He 
found that not only was the amount of gas given off 
greatly augmented, but it lowered the weight of tar, though 
it doubled the amount of free carbon in it by specific 
gravity being increased. 

Experimenting with a caking coal, Mr Wright found 
that as the make of gas increased so correspondingly did 
the specific gravity of tar, although the quantity showed a 
decrease. 

The following Table shows the increases :— 


Yield of Gas 
per ton. 


of Tar. 

i,086 degrees. 


Specific Gravity 


6,600 cub. ft. 
7,200 „ 

8,900 „ 

10,162 ,, 


11 , 7 °° „ 


1,120 

T.T/in 



EFFECT OF HEAT ON GAS AND BYE-PRODUCTS. 71 

He also showed that although the percentage of free 
carbon is augmented, the lighter constituents in the tar are 
decomposed into gas. 

One of the most interesting points which Mr Wright 
noted was the very large increase in the yield of cyanogen. 
At low temperature this product is yielded in very small 
quantities, and at a higher temperature it is found to 
increase by about ten times its quantity. 

At this temperature the ammonia is found to have 
decreased, and no doubt at higher temperatures the 
ammonia is decomposed, and the nitrogen set at liberty 
combines with the free carbon forming cyanogen, whilst 
the excess hydrogen remains in the gas as usual. 

The accompanying Table shows the decrease and in¬ 
crease in some of the various products on carbonising coal 
at various heats :— 


Table showing Effect of Heat on Gas and Bye-Products. 


Products- 

Low Heats, 
i,6oo° to 
1,800° Fahr. 

Medium Heats, 
1,800° to 
2,200° Fahr. 

High Heats, 
2,200° to 2,800° 
Fahr. 

Gas quantity 

Small - 

Medium - 

Large. 

Illuminating power 

Tar- 

High - 

Lower 

Lowest. 

Pitch - 

Low 

Higher 

Highest. 

Ammonia - 

High - 

Medium - 

Lower. 

Phenols 

High - 

Medium - 

Lower. 

Ammonia 

Small - 

Maximum 

Lower. 

Carbon bisulphide 

Small - 

Medium - 

Maximum. 

Sulphuretted hydrogen - 

Small - 

Medium - 

Maximum. 

Carbon dioxide 

Small - 

Medium - 

Maximum. 

Cyanogen 

Small - 

Medium - 

Maximum. 

Coke - 

Soft - 

Harder 

Hardest. 


Mr Lewis T. Wright gives the following interesting 
Table ; he examined the composition of the tar, yielded by 
the same kind of coal, at different carbonising temperatures, 
between 600 and 800 degrees Cent.:— 
















72 


PRODUCTS OF CARBONISATION. 



I. 

II. 

III. 

1 IV. 

V. 

Cubic feet of gas—yield I 
per ton of coal - - f 

6,600 

7,200 

8,900 

10,162 

11,700 

Specific gravity of tar - 
Composition of tar per 

1.086 

1.102 

1.140 

1.154 

1.206 

cent., by weight— 
Ammoniacal liquor - 

1.20 

1.03 

1.04 

1.05 

0.383 

Crude naphtha - 

9.17 

9.65 

3-73 

3-45 

0.995 

Light oil 

10.50 

7.46 

4-47 

2.59 

0.567 

Creosote oil 

26.45 

25.83 

27.29 

27.33 

19.440 

Anthracene oil - 

20.32 

15-57 

18.13 

13-77 

12.280 

Pitch - 

28.89 

36.80 

41.80 

47.67 

64.080 


This Table shows how the temperature of carbonisation 
affects not only the gas, but the composition of the bye- 
products are affected to an enormous extent. These results 
were undoubtedly got from a good coal, and would be still 
more marked in a poorer class of coal where the gas 
engineer’s aim and object was to keep up his make per 
ton of coal. The bye-products would suffer, and undoubtedly 
it is possible to have the heats sufficiently high to have a 
tar which would be useless for working up the bye-products, 
as it would practically consist of pitch and ammoniacal 
liquor. 

Lunge says on this interesting subject: Most gas 
engineers try above everything to get as much gas as 
possible out of the coal, and therefore distil at the highest 
possible temperature. Up to a certain point this is quite 
rational, and is even unavoidable from the nature of the 
material now universally employed for gas retorts, viz., 
fire-clay. This point seems to be reached when the fatty 
compounds are split up as far as possible before any con¬ 
siderable separation of free carbon has taken place. 

Beyond this point more gas will be got, but its illuminat¬ 
ing power will be less; the tar will at first contain a little 
more of the valuable anthracene, but at the same time even 
more of naphthalene, which has much less value, and of 









EFFECT OF TEMPERATURE ON RESIDUALS. 73 

phenanthrene, pyrene, chrysene, diphenyl, &c., which are 
quite valueless, so that its value will on the whole be less. 

There is also a reduced quantity of tar, if the tempera¬ 
ture in the retorts is raised higher. The separation of free 
carbon in the retorts and the tar is also largely increased. 
In England the usual temperature of working seems to be 
about 1,100 degrees Cent. ( = 2,000 degrees Fahr.). 

But, properly speaking, it should be experimentally 
ascertained (and that for every class of gas-coal specially) 
at what temperature the maximum of lighting power is 
obtained, even if concentrated in a smaller volume of gas, 
and also at what temperature we can get a maximum yield 
of benzene, toluene, phenols, and anthracene in the tar. 
Probably the two maxima will not coincide, and it will then 
be a matter of business calculation whether the one or the 
other is to be worked for. It is evident that the market 
prices of the bye-product must influence this consideration. 

Certain statements have been made as to the shape of 
the retorts affecting the tar; these have evidently been 
wrongly interpreted, the difference in the tar being un¬ 
doubtedly due to the length of time the gas hangs about 
in the retort, which causes decomposition of the tar and 
gas. 

The quality of the tar now made from various kinds of 
cannel coal is very different from that obtained formerly. 
Twenty years ago, when low heats were used at the gas¬ 
works, as much as 8 per cent, of naphtha (*>., benzene and 
its homologues) was obtained by distillation with steam. 
This diminished slowly as the heat employed at the gas¬ 
works increased, until it had fallen a few years ago to about 
3 per cent. 

The naphtha from Scotch tar was always rich in toluene, 
and contained less benzene than from ordinary bituminous 
coal. It contains little naphthalene, and very little anthra¬ 
cene, so little that its extraction is not worth while. It also 
contains considerable quantities of paraffin, but mostly of a 
low melting point. Naphthalene and paraffin seem to go 


74 


PRODUCTS OF CARBONISATION. 


together; wherever there is much of the one, the other is 
always present too, with few exceptions. Coal-tar is a 
black, more or less viscid fluid of peculiar smell, generally 
of phenols, sp. gr. from i.i to 1 . 2 , according to the method 
of manufacture. 

Coal-tar is an extremely complex mixture of chemical 
compounds, some of which have not yet been completely 
isolated. The tar contains nitrogenous compounds chiefly 
of a basic nature, owing to the nitrogen which originally 
exists in the coal and sulphur compounds derived from 
pyrites, &c., which are always found in the coal. 

James M‘Leod, in the Journal Soc. Chem. Ind vol. xxvi., 
p. 137, says that on submitting coal to destructive distilla¬ 
tion, the nitrogen present in it is partly retained by the 
coke, and partly eliminated as free nitrogen, which at the 
moment of liberation probably combines with hydrogen 
and with carbon to form ammonia and cyanogen respec¬ 
tively, and partly remains as free nitrogen. It also remains 
combined with carbon and nitrogen to form bases, such as 
pyridine. 

The summary of his results is :— 


Per Cent, of 
Total Nitrogen. 

Nitrogen in the coke - - - 58.30 

„ „ tar - - - - 3.90 

„ „ ammoniacal liquor - 17.10 

„ „ cyanogen - - - 1.20 

„ ,, in gas (by difference) - 19.50 


100.00 


He also gives the average nitrogen in coal, 1.434 per 
cent., in coke from coal, 1.374 per cent., which gives the total 
nitrogen in the coke 58.3 per cent. 

Lunge gives the following list of compounds hitherto 
found in coal-tar, or reasonably presumed to exist in it:— 




LIST OF COMPOUNDS IN COAL-TAR. 


75 



Formula. 

Melting 

Point. 

Boiling Point. 



Deg. Cent. 

Deg. Cent. 

A. Hydrocarbons. 

I. Methane Series , CnH 2N + 2 . 




Methane . 

ch 4 



Ethane . 

C 2 I 1 6 



Propane . 

c 3 h 8 


- 20 

Butane (normal) . 

c 4 h 10 


+ I 

Pentane (normal) 

c 5 i-i 12 

liquid 

37-39 

Isopentane 

c 5 h 12 

3 ° 

Hexane (normal) 

c«h 14 


69-71 

Heptane (normal) 

c 7 h 16 


98 

Ethylisoamyl 

Qh 16 


90.3 

Octane I. 

LgHig 


119-120 

„ II. 


9 9 

124 

Nonane I. 

CgHoo 

99 

130 

„ II. 

C9H20 

9 9 

150.8 

Decane I. 

U10H22 

99 

158-161 

„ II. 

Undecane 

U10U22 

9 9 

170-171 

c u h 24 


180-182 

Duodecane 

C 12 H 26 

" 

200-202 

Tredecane 

Ci 3 H 28 


218-220 

Quatuordecane . 

C14H30 


236-240 

Quindecane 

Ci 5 pl 32 

9 9 

258-262 

Sedecane 

C 16 H 34 

\ c 17 h 36 ) 

9 9 

280 

Solid paraffins 

UJ 

40-60 


II. Ethylene Series, CnH 2 N. 




Ethylene 

c 2 h 4 


- no 

Propylene 

C 3 H fi 

... 

9 9 

Butylene (normal) 

c 4 h 8 


-5 

Pseudobutylene . 

c 4 h 8 


+ 1 

Isobutylene 

c 4 h 8 


-8 

Amylene.... 

c 5 h 10 

liquid 

+ 39 

Hexylene 

c 6 h 12 

99 

68-70 

Heptylene 

c 7 h 14 

99 

96-99 

III. Hexahydro - addition - pro¬ 
ducts of the Benzene Series, 
CnH 2 N (Naphthenes). 




Hexahydrobenzene 

QH12 

liquid 

69 

Hexahydrotoluene 

C 7 H 14 

,, 

97 

Hexahydroisoxylene 

QUig 

99 

118 














PRODUCTS OF CARBONISATION. 


;6 



Formula. 

Melting 

Point. 

Boiling Point. 



Deg. Cent. 

Deg. Cent. 

A. Hydrocarbons— contd. 

IV. Acetylene Series , C11H2N-2. 




Acetylene 

c 2 H 2 

... 

... 

Allylene .... 

C 3 H 4 


18 

Crotonylene 

c 4 h ( . 

liquid 

Valylene (?) 

C 5 H 8 

... 


Hexoylene 

c 6 h 10 

liquid 

80 

Higher members. 

c 12 h 20 

99 

210 

1 ) 9 9 

C 14 H 21 

99 

24O 

99 99 

c 16 h 28 

9 9 

280 

V. Tetrahydro - addition - pro¬ 
ducts of the Benzene Series, 
CnH 2 N-2 (Naphthylenes). 




Tetrahydrobenzene 

C(jH ]() 

liquid 

82 

Tet rahy d rotol uene 

c v h 12 

9 9 

IO3-IO5 

Tetrahydroxylene 

C 8 H 14 

9 9 

I29-I32 

VI. Series CnH 2 N- 4 . 




Cyclopentadiene . 

c 5 h (5 

liquid 

42.5 

Nonone .... 

C y H 14 

9 9 

174 

VII. Aromatic Dihydro - addi¬ 
tion • products , C n H 2 N~4 
(Terpenes). 




Dihydrobenzene . 

c 6 h 8 

liquid 

81.5 

Dihydrotoluene . 

C 7 H 10 

9 9 

IO5-I08 

Dihydroxylene . 

c 8 h 12 

99 

132-134 

Dihydrocymene . 

^ 10^16 

9 9 

174 

VIII. Benzene Series, OH 2 n-6. 




Benzene .... 

C 6 H 6 

4*5-7 

80.4 

Toluene .... 

c 7 h 8 

liquid 

III 

Xylene . . . . 

Q^IO 

) 9 


Orthoxylene . 

99 

I4I-I42 

Metaxylene 

... 

9 9 

139 

Paraxylene 


.15 

I37-5-I38 . 

Ethylbenzene 

C 8 H 10 

liquid 

137 

Pseudocumene 

c 9 h 12 

99 

169.5 

Mesitylene 

c 9 h 12 

99 

I63 

Hemellithol 

c 9 h 12 


175 

Durene .... 

QluHl 4 

80-81 

I96 

. . . 

Other tetramethyl benzenes 

... 

IX. Sfyrolene(?), CnH 2N -8. 

c 8 h 8 

liquid 

145 

Hydride of styrolene (?) . 

C 8 H 10 

9 9 






























LIST OF COMPOUNDS IN COAL-TAR. 


77 



Formula. 

Melting 

Point. 

Boiling Point. 

A. Hydrocarbons— 


Deg. Cent. 

Deg. Cent. 

X. Indene , CnH2N - to 

C 9 H 8 

liquid 

177-178 

Hydrindene 




XI. Naphthaleiie, C n H 2 N -12 

CioPIg 

79 

2l8 

Naphthalene dihydride . 

QoH 10 

liquid 

200-210 

,, tetrahydride 

c 10 h 12 

9 9 

190 

a-Methylnaphthalene 

C n H 10 

99 

24O-243 

/3-Methylnaphthalene 

Ql^lO 

32.5 

24I-242 

Dimethylnaphthalene 

Q2H12 

liquid 

262-264 

XII. Acenaplithene, C1-1H2N-14 . 

^12^10 

95 

277-5 

Acenaphthene hydride . 

^•12^12 


260 

Diphenyl 

C ia H 10 

70.5 

254 

XIII. Fluorene , CnH 2 N-i6 

Q3H10 

113 

295 

XIV. Anthracene , C n H 2 N-i8 • 

Q4H10 

213 

360 

Anthracene dihydride 

Q4H12 

106 

305 

,, hexahydride . 

Ci4^16 

63 

290 

,, perhydride . 

C14H24 

88 

250 

Methylanthracene (?) 

Ci5^J2 

208-210 

above 260 

Dimethylanthracene (?) . 

Ci6^14 

224-225 


Phenanthrene 

C 14 Hio 

99-100 

340 

Phenanthrene tetrahydride 

C 14 H u 

liquid 

300-304 

,, octohydride 

ChH 18 

9 9 


,, perhydride 

c 14 h 24 

-3 

270-275 

Pseudophenanthrene (?) . 

CisH 12 

115 

above 360 

Synanthrene (?) . 

Ci4^10 

189-195 

above 360 

Fluoranthrene (?) 

Ci5^10 

109 

Pyrene .... 

c 16 h 10 

148 

above 360 

Chrysene 

CisHi2 

250 

436 

Chrysene hydride 

Ci 8 H28 

liquid 

360 

,, perhydride 

Chrysogene 

Cl8^30 

115 

353 

Ci8^18 

280-290 

350 

Retene .... 

98-99 

Retene dodecahydride 

Cl8^30 

liquid 

336 

Succisterene (?) . 

^22^14 

160-162 

above 300 

Picene .... 

364 

518-520 

Picene eikosihydride 

0^34 

liquid 

360 

,, perhydride 

C22H30 

175 Q 

360 

Benzerythrene 

Q4H18 

307-308 


Bitumene 





















78 


PRODUCTS OF CARBONISATION. 



Formula. 

Melting 

Point. 

Boiling Point. 



Deg. Cent. 

Deg. Cent. 

B. OXYGENISED COMPOUNDS. 




Water .... 

h 2 o 

O 

IOO 

Methylic alcohol (?) 

ch 4 o 

liquid 

63 

Ethylic alcohol (?) 

c 2 h 6 o 


7«-5 

Acetone .... 

c 3 h 6 o 

> > 

56 

Ethylmethylketone (?) 

c 4 h 8 o 


77 . 5-81 

Adds and Phenols. 




Acetic acid 

c 2 h 4 o 2 

16 

119 

Benzoic acid 

c;h 6 o 2 

121 

249 

Phenol (carbolic acid) 

c 6 h 6 o 

42 

184 

Orthocresol 

c 7 h 8 o 

32 

188 

Paracresol 

J> 

36 

199 

Metacresol 

33 

3-4 

201 

Xylenols: ortho i, 2, 4 . 

^S^loO 

62 

225 

meta 1, 2, 3 . 

3 3 

73 

216 

meta 1, 3, 4 . 

3 3 

26 

2 II -5 

para 1, 3, 4 . 

3 * 

74-5 

2 II- 2 I 3 

a-Naphthol 

Cio^gO 

94-96 

278-280 

/ 3 -Naphthol 

' i 

>> 

122 

294 

Phenols of the A nthracene Series ( 7 ). 




a-Pyrocresol 

C lr ,H 14 0 

196 

350 

/ 3 -Pyrocresol 

33 

124 

Y-Pyrocresol 

3 3 

105 

... 

Rosolic acid (?) . 

Ci 9 Hi 4 0 3 


Brunolic acid (?) . 



Cumarone 

c 8 h 6 o 

liquid 

168.5-169.5 

/-Methyl-cumarone 

c 9 h 8 o 

33 

197-199 

w-Methyl-cumarone 

>5 

3 3 

i 95" i 96 

0-Methyl-cumarone 

33 

„ 

190-191 

0./.-Dimethyl-cumarone . 


3 3 

221-222 

m.p. -Dimethyl-cumarone 


33 

221 

0. m. -Dimethyl-cumarone 

>> 

33 

216 

C. Sulphuretted Compounds. 




Hydrogen sulphide 

h 2 s 



Ammonium sulphide 

(nh 4 ) 2 s 



,, sulphocyanide 

(NH 4 )CNS 

... 


Sulphur dioxide . 

so 2 



Carbon bisulphide 

cs 2 

liquid 

47 

,, oxysulphide 

cos 

Mercaptanes 


... 


Alliol (?) .... 




Thiophene 

c 4 h 4 s 

liquid 

48 





















LIST OF COMPOUNDS IN COAL-TAR. 


79 


C. Sulphuretted Compounds 
— continued. 

a-Thiotolene 

j 3 -Thiotolene 

a-a-Thioxene 

a-/ 3 -Thioxene 

a-^-Thioxene 

/ 3 -/ 3 -Thioxene 

a-/ 3 -/i-Trimethylthiophene 

Tetramethylthiophene 

Biophen . 

cd-a-Dithienyl 

jS 1 -j 3 -Dithienyl 

Trithienyl 

Thionaphthene . 

Thiophthene 


D. Chlorinated Compounds. 
Ammonium chloride 


E. Nitrogenised Compounds. 
I. Basic. 

Ammonia 

(Ammonium compounds men¬ 
tioned under C., D., and E., II.) 
Methylamine, ethylamine, &c. . 

Cespitine (?) 

Aniline .... 

Homologues of aniline (?) 

Pyridine .... 

a-Picoline 

7-Picoline 

a-a-Lutidine 

a-7-Lutidine 

a-^-Lutidine 

/3-7-Lutidine 

jS-^-Lutidine 

7-Ethylpyridine . 

a-7-a 1 -Collidine . 

a 1 -^3-7-Collidine . 

Parvoline (?) 

a-^^-^-Tetramethylpyridine 
Coridine (?) 

Rubidine (?) 


Formula. 

Melting 

Point. 

Boiling Point. 


Deg. Cent. 

Deg. Cent. 

c 8 H 6 s 

liquid 

1 13 

9 * 

9 9 

1 13 

CfiH 6 S 

9 9 

135-136 

99 

9 9 

136-137 

99 

99 

137-138 

99 

9 9 

136-137 

C^HjoS 

99 

163 

c 8 H 12 s 

9 9 

182-184 

C4H4S2 

99 

165-170 

c 8 h 6 s 2 

33 

... 

* 9 

132.4 


c 12 H 8 s 3 

147 

357 

c 8 h 5 s 

3 °- 3 1 

220-221 

c 6 h 4 s 2 

liquid 

224-226 

npi 4 ci 


... 

nh 3 



c 5 h; 3 n 

liquid 

... 

9 9 

95 

c 6 h 7 n 

-8 

182 

C,H«N 

liquid 

116.7 

c 6 h 7 n 

9 9 

135 

9 9 

99 

(?) 

c 7 h 9 n 

99 

142 

99 

99 

157 

99 

9 9 

(?) 

99 

99 

163.5-164.5 

9 9 

9 9 

169-170 

99 

99 

164-166 

C s H n N 

99 

171-172 

99 

99 

165-168 

c 9 h 13 n 

99 

188 

99 

99 

232-234 

C I0 H 15 N 

99 

211 

C n H l7 N 

99 

230 























So 


PRODUCTS OF CARBONISATION. 



Formula. 

Melting 

Point. 

Boiling Point. 



Deg. Cent. 

Deg. Cent. 

E. Nitrogenised Compounds 




— continued. 




I. Basic — continued. 




Viridine (?) . . 

c 12 h 19 n 

liquid 

251 

Leucoline (Chinoline) 

c 9 h 7 n 


239-240 

Isoquinoline 

c 9 h 7 n 

18-23 

236-237 

Chinaldin (a-Methyl-quinoline) . 

Cj 0 H 9 N 

liquid 

243 

Iridoline (7-Methyl-lepidine) 

c 10 h 9 n 

,, 

252-257 

Cryplidine (Dimethyl-quinoline). 

C n H n N 


274 

Tetracoline-octacoline (?) 




Acridine 


in 

above 360 

2-Methylacridine 

C 14 H n N 

134 


4-Methylacridine 

> > 

88 


2-4-Dimethylacridine 

c 15 h 13 n 

71 


II. Not Basic. 




Pyrrol .... 

c 4 h 5 n 

liquid 

133 

Ammonium cyanide 

cn.nh 4 



Methylic cyanide (acetonitrile) . 

CHo—CN 

liquid 

77 

Benzonitrile 

c 6 h 5 cn 


191 

Methylic isocyanide 

c 2 h 3 n 

238 

59-6 

Carbazol 

c 12 h 9 n 

355 

Phenyl-a-naphthyl-carbazol 

QlgHuN 

225 

above 440 

Phenyl-/?- „ 


230 


F. Free Carbon. 

Cx 




It is sometimes necessary to test a sample of tar in the 
laboratory to ascertain its market value. The following is 
the usual method, devised by Lunge, and given in his “ Coal- 
Tar and Ammonia” :— 

In a scientific laboratory it is difficult to employ more 
than a kilogram or two for each distillation. The results 
thus obtained will never exactly coincide with those obtained 
in manufacturing practice, but experience proves that they 
give a very good idea of the general quality of the tar. It 
would be most convenient to employ for such quantities 
distilling vessels made of metal, and I would indeed strongly 
recommend this for factory laboratories; all the more as it is 











DISTILLATION OF COAL-TAR. 81 

thus easy to work upon very much larger quantities. But 
in scientific laboratories where, for more reasons than one, 
it is out of the question to distil a hundredweight of tar, or 
some such quantity, it will be always preferred to accurately 
obseive the progress of the operation, and this it is only 
possible to do in glass retorts. 

My retorts were tubulated, holding about 5 litres, and 
weie heated in a kind of sand air bath—that is, in a suit¬ 
ably-shaped thin wrought-iron dish, the bottom of which 
was covered by a layer of sand 1 cm. thick. About half 



Fig. 25.—Apparatus for Distilling a Sample of Tar. 


of the retort was within the dish, and the whole of it, down 
to the sand, and including the upper part of the neck, was 
wrapped round with wire gauze. The heating was done by 
a Fletcher’s gas stove, placed in a large flat pan partially 
filled with sand. Hence, in case of an accident, the tar 
would have first to run into the upper pan, forming the 
sand air bath, and anything boiling over from this would 
have been caught in the lower pan. The tubulure of the 
retort was fitted with a twice perforated cork, holding a 
thermometer and a tube, drawn out into a capillary at the 
lower end, with the object of passing a minute current of 























82 


PRODUCTS OF CARBONISATION. 


air bubbles through the liquid, in order to prevent bumping. 
This precaution, first introduced by Dittmar, and also em¬ 
ployed by Watson Smith, was found to be very useful 
indeed, but it seems possible that the air current might 
carry away a minute quantity of benzene. 

The retort was, during the first part of the operation, 
connected with a Liebig’s condenser, so long as the distil¬ 
late remained entirely liquid. When it began to partly 
solidify—that is, between 170 and 180 degrees—the cooler 
was removed; and since now the last portions of water 
had been volatilised, and no more bumping was to be 
apprehended, the current of air was discontinued. The last 
of the water escaped between 140 and 170 degrees with 
explosive violence. 

The distillation of 2 \ to 3 litres of tar took about eight 
hours. It is decidedly advisable to carry the distillations 
through without any interruption, both because the heating 
up, after the contents of the retort have been semi-solid or 
solid on cooling, is always an awkward operation ; and 
because during the cooling down and the heating up a 
considerable quantity of substance passes over far below 
their proper boiling points. 

The distillates were collected in tared, narrow, graduated 
cylinders, and after cooling down they were measured and 
weighed. 

The fractions were made in the way stated below. But 
although, as a matter of course, every precaution was taken 
to keep the temperature as constant as possible, still, with¬ 
out any recognisable reason, the thermometer showed con¬ 
siderable oscillations, and sometimes went down to 20 
degrees without any diminution in the rate of distillation. 

It cannot be said that such assays are exact analytical 
operations. The fractions will differ to some extent, as the 
distillation proceeds more or less slowly. Each time, when 
substances are poured from one vessel to another, small 
losses are unavoidable, although in the case of the higher 
boiling substances the vessels were rinsed with ether, which 


DISTILLATION OF COAL-TAR—FRACTIONS. 83 

was subsequently evaporated. In washing and drying, in 
the case of the first distillates also by evaporation, small 
losses will occur, which become all the more important 
when the absolute quantity of substance is only slight. 

If the tar has not been previously dehydrated, the work 
must begin with that operation, which is of great import¬ 
ance. It is not feasible to go as far as 100 degrees, because 
then the tar would lose many valuable portions, especially 
as the operation takes so much time. Hence, the dehydra¬ 
tion was performed in the retort itself, turning its neck 
upwards, and connecting it with a cooler, inclined down¬ 
wards, in order to collect any benzene escaping along with 
the water. The heating was continued in this manner to 
60 to 70 degrees for a full fortnight; every morning, 
before recommencing, the water collected in the meantime 
on the surface was removed by a pipette. For all that, 
some water remained behind, evidently in chemical com¬ 
bination with phenol, pyridine, &c., and this could only be 
removed by distillation. 

The fractions were made as follows:— 

1. Light oil, up to 170 degrees. 

2. Middle oil, up to 230 degrees (carbolic oil). 

3. Creosote oil, up to 270 degrees. 

4. Anthracene oil, up to the close of the distillation, 
which was continued as long as anything would come over ; 
this explains why the pitch was extraordinarily hard. 

The above fractions were treated in the following 
manner :—The light oil was first agitated with caustic soda 
solution of sp. gr. 1.1, and the contraction of volume was 
calculated as “phenols.” The oil was then washed with 
water, with concentrated sulphuric acid, and again with 
water, and the total contraction was calculated as “ loss by 
washing.” The residual oil was distilled, and the fractions 
coming over up to 100 and 140 degrees were separately 
collected. The distillate up to 140 degrees was considered 
as “crude aniline benzol,” and its degree of purification 
examined by nitrification with ordinary mixture of acids. 


8 4 


PRODUCTS OF CARBONISATION. 


The portion remaining behind at 140 degrees was calculated 
as “ heavy naphtha ” ; it must, of course, leave a good deal 
of residue on rectification, and this residue will practically 
go to the creosote oil; but, on the other hand, some heavy 
naphtha will come back from the “ middle oil,” and on the 
small scale it was impossible to say how far this would 
compensate for the residue left on rectifying. The small 
quantity of liquid also made it impossible to separate the 
“ aniline benzol ” into benzene, toluene, and xylenes. From 
the middle oil and the creosote oil a quantity of naph¬ 
thalene crystallised on cooling. This was filtered through 
calico, strongly pressed, and calculated as “ crude naphtha¬ 
lene.” The liquid portion of the oil (making allowance for 
the mechanical loss in pressing) was treated with caustic 
soda solution, and the contraction of volume again set down 
as “ phenols.” 

The anthracene oil, after cooling, was filtered through 
calico, the crude anthracene was pressed cold, then spread 
out upon porous earthenware slabs, heated in an air bath 
to 30 to 40 degrees, pressed while warm, and weighed. It 
was now analysed by the “ Hochst ” test ; but since in the 
trade anthracene is usually sold as 30 or 40 per cent., 
three times the weight of pure anthracene was deducted 
from the weight of crude anthracene oil, to get at the figure 
for liquid anthracene oil. 

The pitch was tested for its softening point by heating 
a piece the size of a pea on a wire in an air bath beside a 
thermometer, until, by pressing with the fingers, it proved 
to be distinctly plastic. 

The water bath did not suffice for this purpose. It was 
further tested for “ carbon,” one of the most tedious parts 
of the work. For this purpose it was extracted alternately 
with boiling benzene and carbon disulphide, but it took 
many days’ toil. The solvents did not show any but a 
faint colour, and left no more residue when evaporated on 
a watch glass. 

This operation must be carried out with the greatest 


SPECIFIC GRAVITY OF TAR. 


85 


caution, since otherwise fine particles of carbon will pass 
through the filter; for this reason Soxhlet’s extracting 
apparatus, otherwise so convenient, could not be em¬ 
ployed. 

The specific gravity of tar cannot be estimated by 
means of an ordinary specific-gravity 
bottle, which is too difficult to fill ex¬ 
actly and to clean in this case. Lunge 
employed a “weighing bottle” of the 
shape shown in Fig. 26, with a glass 
stopper provided with a rill a y 2 mm. 
wide. The operation is performed, as 
when estimating the specific gravity of 
solids, by filling the glass only parti¬ 
ally with tar and then completely with 
water. First the glass is weighed empty 
(< a), and again after being filled with 
water at 15 degrees Cent. (£). It is then 
dried, tar is poured in up to about two- 
thirds of its height, and the glass with¬ 
out its stopper is placed for about an 
hour in hot water till all air bubbles 
disappear. After cooling, the weight of „ 

53 ’ • 1 / Special Specific Gra- 

the glass plus the tar is determined ( £■). vity Bottle for Tar. 

Now water is poured in, the stopper is 
inserted, the water issuing from the rill is removed, the 
whole is allowed to stand in a vessel filled with water of 
known temperature, and the weight is again taken (d). 
The specific gravity (S) sought is:— 

g_ c-a 

b + c — (ci + d) 

In most cases the specific gravity of tar, after dehydration, 
is a sufficient guide as to its quality. 

According to Kohler ( Zsch.f angw. Cli., 1888, p. 677), 
it depends mainly upon the percentage of free carbon as 
shown in the following Table :— 









86 


PRODUCTS OF CARBONISATION. 


Origin of Tar. 

Specific 

Gravity. 

Free 

Carbon. 

Origin of Tar. 

Specific 

Gravity. 

Free 

Carbon. 

Heidelberg - 
Darmstadt - 
Baden Baden 
Bockenheim- 
F rankfort 
Bamberg 
Neustadt 

1.220 

1 . 215 
1 . 19 S 

1.190 

I.l8o 

1.175 

1.172 

per cent. 

2375 

2O.93 

19.92 

18.24 

1570 

15.15 

15.07 

Caunstadt 

Roltweil 

Karlsruhe 

Ulm - 
Heilbronn 

Oos 

I.164 

I.l6l 

1 .155 

1.150 

1.150 

1.145 

per cent. 

I4.05 

14.00 

13-50 

12.44 

12.42 

5.00 


The estimation of free carbon in tar is decidedly im¬ 
portant. Kraemer extracts the tar with forty times its 
weight of xylene. It is more expeditious to heat io grams 
of tar with a mixture of 25 grams glacial acetic acid, and 
25 grams of toluene, pouring the liquid on to two filters of 
equal weight, placed one within the other, and washing 
with boiling benzene until this runs off colourless. After 
drying, the outer filter is used as tare in weighing the inner. 

The more free , carbon, the more viscous the tar, and 
the more easily will it froth during distillation. Tars con¬ 
taining less free carbon, that is of less specific gravity, are 
richer in benzene and other light hydrocarbons than those 
containing more free carbon. But this holds good only to a 
certain limit, say 15 to 17 per cent, free carbon. Above this 
tars of equal percentage of free carbon may furnish either 
more anthracene, or more benzene, &c., according to their 
origin ; but if they contain considerably more carbon than 
17 per cent., they are sure to yield less valuable products of 
all kinds and more pitch. If K is the percentage of free 
carbon in the pitch, and k the percentage of free carbon 

in the tar, the yield of pitch is 1C ^ ^ . Medium hard pitch 

contains about 28 per cent, free C ; for normal tar with 
16 per cent. C we thus find :— 

100 x 16 

= 57 per cent., 


28 




















HOCHST TEST FOR ANTHRACENE. 


87 


which is in sufficient agreement with experience. It is 
not proposed here to enumerate all the tests and analyses 
of the various compounds, &c., in tar; for further and 
complete information, Lunge, “Coal-Tar and Ammonia,” 
must be consulted together with recent literature on the 
subject. 


Hochst Test for Anthracene. —1 gram of anthracene 
cake is dissolved in 45 c.c. of glacial acetic 
acid in a half litre flask, to the mouth of 
which an inverted condenser is attached. 

The solution is boiled, and to this is added 
from a tap funnel (fitted to the top of the 
inverted condenser) a solution of 15 grams 
of chromic acid in 10 c.c. of glacial acetic 
acid, diluted with its own volume of water. 

The contents of the flask must be kept in 
gentle ebullition, and the chromic acid must 
be added drop by drop, the operation taking 
about two hours. The liquid in the flask 
must then be kept boiling for two hours 
longer, when the heat is removed, and the 
flask and contents left at rest for twelve 
hours. 400 c.c. of water are now added, 
and after leaving for three hours, the con¬ 
tents of the flask are filtered ; the anthra- 
quinone collected on the filter is washed 
in turn with cold water, boiling dilute solu¬ 
tion of caustic potash (about 2 per cent.), and then with 
hot water. 

The anthraquinone is transferred by washing from the 
filter to a porcelain dish, and then dried at 100 degrees Cent. 
Ten times its weight of fuming sulphuric are now added, 
the dish is heated on a hot-water bath for ten minutes, and 


Fig. 27. — Hochst 
Test for An¬ 
thracene. 


then placed in a moist atmosphere for twenty-four hours; 
200 c.c. of water are now added, filter, and wash mass on 
filter as before. The contents of the filter are transferred 









88 


PRODUCTS OF CARBONISATION. 


to a dish which is dried at ioo degrees Cent, and weighed. 
The dish is then heated to drive off the anthraquinone, 
the dish is cooled, and again weighed ; the difference be¬ 
tween the two weighings gives the amount of anthraquinone 
obtained from I gram of the anthracene cake. Multiplying 
this by 85.58 gives the percentage of anthracene found in 
the 1 gram of cake ; this is easily calculated into the per¬ 
centage of anthracene in the tar. 


Benzene.— The methods and procedure are too numer¬ 
ous to mention, but the general distillation of benzene for 
commercial purposes is carried out in an ordinary retort, 
with Liebig condenser attached. The great cause of differ¬ 
ent results is where to place the bulb of the thermometer 
which is generally in the liquid. G. E. Davies finds in 
90 per cent, and per cent, benzole:— 


Pure benzene 
„ toluene 
„ xylene 


90 per cent. 

75 

24 


f g per cent. 

5 ° 

40 

10 


Estimation of Sulphur in Benzole .—A weighed quantity 
of the benzole is burnt on the gas referee’s apparatus. A 
good method is: fill an ordinary spirit lamp with benzole 
and weigh it, place it in the trumpet tube, in the position 
usually 7 occupied by the Bunsen burner, placing the usual 
carbonate (sesqui) of ammonia round inside the tube, and 
light the lamp, taking care that it is not too high and 
that it does not smoke. After finish of test wash down 
the apparatus, boil liquor with hydrochloric acid, and pre¬ 
cipitate sulphur as BaS 0 4 . Weigh lamp to ascertain the 
amount of benzole burnt. The weight of BaS 0 4 multiplied 
by .13734 gives the amount of sulphur in quantity of benzole 
used. 

Mr W. Irwin before the Chemical Industry in 1901 gave 
the above method, but he mixed a certain portion of 
alcohol or methylated spirit with it, first of all carrying 


AMMONIUM SULPHATE. 


89 


out a blind test to ascertain the amount of sulphur in the 
methylated spirit. The amount of sulphur in benzole 
varies from about 0.40 per cent, to 1.00 per cent. Un¬ 
doubtedly in a very short time a market will be opened 
for a rectified benzole for the use of internal combustion 
motors, as the petrol used now for motor cars, &c., is not 
such a very great 
difference from ordi¬ 
nary benzole. 

Ammonium 
Sulphate. —It is 

not intended to 
treat of the manu¬ 
facture of sulphate 
of ammonia, but 
only the analysis of 
this material after 
manufacture. Sul¬ 
phate of ammonia is 
generally tested for 
(1) percentage of 
water at 100 degrees 
Cent., (2) the per¬ 
centage of NH 3 . 

The Fertilisers 
and Feeding Stuffs 
Act, 1906, Chapter 
27, states : “ Every 
person who sells for 
use as a fertiliser of 

the soil any article which has been subjected to any 
artificial process in the United Kingdom, or which has 
been imported from abroad, shall give the purchaser an 
invoice stating the name of the article, and what are the 
respective percentages (if any) of nitrogen, soluble phos¬ 
phates, insoluble phosphates, and potash contained in the 



Fig. 28.—Apparatus for Estimation of Sulphur 
in Benzol. 






















90 


PRODUCTS OF CARBONISATION. 


article, and the invoice shall have effect as a warranty by 
the seller that the actual percentages do not differ from 
those stated in the invoice beyond the prescribed limits of 
error.” 

The Act further gives power to appoint analyst and 
sampler, power to have fertiliser or feeding stuff analysed, 


&c. &c. 


i. Estimation of Moisture .—The amount of free moisture 
is determined by drying a weighed quantity to i io degrees 
Cent, until weight is constant, in a flat dish. The loss in 
weight represents the moisture in quantity taken. 



Fig. 29.—Apparatus for Estimation of Ammonia. 


In sampling ammonium sulphate special care must be 
taken. It must be taken quickly, intimately mixed, and 
immediately placed in a well-stoppered bottle, so that no 
loss of moisture takes place. 

2. Estimation of Ammonia .—A known weight of the 
salt is taken (say about 10 grams), and dissolved in 500 c.c. 
of distilled water ; 50 c.c. of this solution are distilled with 
caustic potash or soda, and the vapour evolved passed into 
15 c.c. of normal sulphuric acid. 

Supposing that on titration 3 c.c. of acid are found to 
have remained unsaturated, then 12 c.c. of acid have been 















ESTIMATION OF AMMONIA. 


91 


neutralised. As 50 c.c. of the solution corresponds to 1 
gram of original liquid (as exactly 10 grams were taken), 
it therefore contains 100x0.017x12 = 20.4 percent, of 
ammonia. From this the nitrogen can easily be calculated. 

If many of these tests are required I find that a good 
method to do a number at a time is to adapt Kjeldahl’s 
apparatus for the determination of nitrogen, consisting of 
six flasks, copper condensers, and flasks on outlet (as per 
sketch). This apparatus can either be purchased with 
horizontal or upright condensers, and takes up very little 
room. 


CHAPTER V. 


ANALYSIS OF CRUDE COAL-GAS . 


The impurities in coal after leaving the condensers are as 
follows :— 


Ammonia, about 
Carbonic acid 
Sulphuretted hydrogen 
Carbon disulphide 
Other sulphur compounds - 
Cyanogen as hydrocyanic acid 


300 grains per cubic foot. 
1,800 „ „ 

1,050 

70 

IO „ ,, 

106 


For the efficient working of a gasworks it is necessary 7 
to know the amount of these various impurities, and often 
at various parts of the plant. It is not proposed to deal 
with any part of the plant, so only methods of analysing or 
testing for these impurities will be given. 

Taking them in the order mentioned :— 


Ammonia.—A normal solution of sulphuric acid is 
made up as described in Chapter I., and likewise a normal 
solution of caustic soda. These are titrated against each 
other. 200 c.c. of the normal sulphuric are taken and put 
into a couple of Woulfe bottles after adding a few drops of 
methyl orange, which gives a yellow colour to the liquid. 
The gas is now bubbled through the acid and then through 
a meter. It is generally advisable to have a third bottle 
with a little distilled water in it which has also had a few 
drops of methyl orange added (if the gas contains many 
tarry particles, a bottle full of cotton wool must be placed 


ESTIMATION OF C 0 2 AND H 2 S. 93 

first to remove this). When the colour in the second bottle 
shows a slight tinge of redness the test must be stopped. 
The bottles are now taken off, well washed out with dis¬ 
tilled water, and titrated back with the normal soda solu¬ 
tion. Now 1 c.c. of the normal acid = 0.017 gram of 
ammonia. 

Therefore, the number of c.c. of acid used multiplied by 
0.017 gives the amount of ammonia in grams in the quan¬ 
tity of gas passed. This is easily calculated to grains per 
100 cubic feet. 

Example :— 

Gas passed = 10 cubic feet. 

Acid taken = 200 c.c. 

Acid used =150 c.c. 

Then 150 x .017 = 2.55 x 10 x 15.4 = 392.70 grains of NH 3 per 
100 cubic feet. 

Carbonic Acid and Sulphuretted Hydrogen.—This 
impurity and sulphuretted hydrogen are sometimes esti¬ 
mated together, but as the method consists of a series of 
U tubes containing calcium chloride, soda lime, and cupric 
phosphate, and it is at times very troublesome to get the 
gas in any appreciable quantity through these materials, I 
prefer to have two meters, and to take the gas from the 
same stream, separating by means of a T, and conducting 
one lot of gas through soda lime alone and the other 
through an acidulated solution of cadmium chloride. Both 
methods will be described :— 

Estimation of Carbonic Acid and Sulphuretted Hydro¬ 
gen .—The reagent employed for the estimation of the 
sulphuretted hydrogen is an impure di-tri-ortho-phosphate, 
the preparation of which is described in Chapter I. 

The reagent is placed in a couple of U tubes, a small 
piece of cotton wool being placed in each stopper to 
prevent any of the reagent being mechanically carried 
forward by the gas. 

The tubes are filled with this material and are then 
connected by rubber tubing together and about 3 cub. ft. 


94 


ANALYSIS OF CRUDE COAL-GAS. 


of clean coal-gas passed through them ; this is rendered 
necessary because the inventor of this method, Mr L. T. 
Wright, F.C.S., found that the cupric phosphate gained in 
weight, but the increase soon reached saturation point, and 
he found the above-mentioned quantity of gas was sufficient 
for this purpose. The tubes are filled as follows:—They 
are first cleaned and dried, and one is filled with powdered 
calcium chloride; the stoppers well greased with vaseline 
or rubber grease; the next two U tubes are filled with 
cupric phosphate, great care being taken that the rough 
and fine portions are well mixed, otherwise the gas will have 
a too free passage through the cupric phosphate, and the 
SH 2 will not be completely removed ; the ground portions 
of the U tubes are now wiped free from dust, a little 
cotton wool placed therein, and the stopper well fitted 
in position. These are now ready for weighing after 
passing the usual quantity of clean coal-gas through 
them. 

The carbon dioxide is absorbed by soda lime. It was 
found more expeditious to use the soda lime a little moist, 
as it absorbed more C 0 2 when moist. The necessary 
amount of moisture can be obtained by exposing the soda 
lime to the action of the air for twenty-four hours. These 
soda lime tubes remain very constant in weight; when clean, 
pure coal-gas is passed through them, and therefore it is 
not necessary to saturate them as in the case of the cupric 
phosphate. It is, however, necessary to pass pure dry 
coal-gas through them before weighing. A couple of U tubes 
are also filled with calcium chloride in the same manner as 
before. These are all weighed and are ready for passing 
the crude coal-gas through them. 

The method of procedure is as follows :— 

In cases (crude gas) where there is ammonia in the gas, 
this must also be removed, and is done as follows :—A U 
tube is filled with pieces of broken pumice which have been 
previously saturated with phosphoric acid. 

As sulphuretted hydrogen is absorbed by vulcanised 


ESTIMATION OF C 0 2 AND H 2 S. 95 

and iron tubing it is necessary to have these thoroughly 
saturated with crude gas before starting the test. 

In this test, as only a small quantity of gas is used, viz., 
about 0.5 cub. ft., it is necessary to have a blow-off cock, 
to keep the service fresh and clean, and also to have an 
average sample of gas. 

The gas first passes through the phosphoric acid tube, 
and the outlet of this is connected to a large cylinder 
(similar to what is used for fouling new oxide of iron) filled 
with calcium chloride. The outlet of this drying cylinder 
is provided with a T-piece which is connected up with a 
Bunsen burner, which is kept burning during the test, keep¬ 
ing a good supply of fresh gas ; the other arm is connected 
on to the soda lime tube, and the outlet of this on to the 
cupric phosphate tube or tubes, and next another calcium 
chloride tube, and then the soda lime tubes, and a calcium 
chloride tube last, and last the gas meter. The reason of 
these calcium chloride tubes is, the first one to make sure 
the gas is dried by the large cylinder, and the one after 
the cupric phosphate to absorb any moisture taken up by 
the dry gas from the cupric phosphate tubes, which must 
be added to the increase in weight of the cupric phosphate 
tube, and similar on the outlet of the soda lime tube. 
After the 0.5 cub. ft. has been passed, as shown by the 
meter register, which should occupy from one to one and 
a half hour, the tubes are disconnected, the stoppers being 
shut first. They are now wiped perfectly dry and are 
ready for weighing. 

The increase in weight of each respective tube of 
material gives the direct amount of SH 2 and C 0 2 in the 
quantity of gas taken, and can easily be calculated to 
grains per 100 cub. ft. The results so obtained will be a 
little high owing to the cyanogen in the gas being absorbed, 
but the error is slight and need not be considered. 


9 6 


ANALYSIS OF CRUDE COAL-GAS. 


Example — 

i. Sulphuretted hydrogen :— 

Volume of gas passed, corrected to N.T.P. = 0.58 cub. ft. 


Weight of inlet calcium chloride tube 

,, ,, ,, ,, after 

Increase - 

Weight of cupric phosphate tube A after 
„ „ „ A before 

SH 9 absorbed - 


1168.9 grains. 
1168.9 „ 


nil 


1200.9 grains. 
1196.1 „ 


4.8 


Tube B cupric phosphate showed no increase. The 
calcium chloride tube after cupric phosphate tube B like¬ 
wise showed no increase; therefore 0.58 cub. ft. contains 
4.8 grains of SH 2 = 827.59 grains per 100 cub. ft. 

Example — 

2. Carboti dioxide :— 


A. Weight of soda lime tube after - 
„ „ „ before 


C 0 2 absorbed - 

B. Weight of soda lime tube after - 
,, ,, ,, before 

C 0 2 absorbed - 

Calcium chloride tube after - 
,, ,, before - 

Increase - 


1468.8 
1460.0 

8.8 

1461.8 
1461.6 

0.2 

1261.3 
1261.o 

o-3 


The increase in the calcium chloride tube is due to 
the dry gas absorbing moisture from the moist soda lime, 
and must be added to the increase of the soda lime; 
therefore 

8.8 + .2 + .3 = 9.3 increase due to C 0 2 ; 

therefore there is 9.3 grains CO., in 0.58 cub. ft. = 1603.44 
grains C 0 2 per 100 cubic feet. 












ESTIMATION OF CARBON DIOXIDE. 


97 


It will be obvious that there is a certain amount of 
error which is multiplied by a very large factor in taking 
such a small quantity of gas. The next method described 
will be a separate test for C 0 2 and SH 2 , but the quantity 
of gas passed can be as much as is desired, and the test 
can be put on and left for a period of twenty-four hours, 
giving a much better average and a far more stringent test. 

Estimation of Carbon Dioxide in Coal-Gas or Oil-Gas .— 
Three large cylinders are filled with soda lime, and weighed 
on an accurate balance, after being blown with pure coal- 
gas. A couple of U tubes are filled with calcium chloride 
as usual. 

The apparatus is connected up as follows :—The gas 
is passed through an oxide purifier to free it of SH 2 , then 
through a meter, then through a large cylinder of calcium 
chloride, and next through one of the small U tubes filled 
with calcium chloride, the outlet of which is connected up 
to inlet of No. i of the soda lime cylinder, which is in turn 
connected to No. 2 and No. 3 soda lime cylinders, the 
other calcium chloride tube coming last, the outlet of which 
is connected on to a burner, and the gas is burnt. The 
inlet also has a blow-away cock which burns the gas by 
means of a burner, so keeping the service fresh. 

The quantity of gas passed can be regulated to any 
amount during the day, but I have found 10 to 12 cub. ft. 
sufficient. The tubes are disconnected and weighed as 
usual, the increase in weight giving the amount of C 0 2 in 
the quantity of gas taken ; this multiplied by 15439 = 
grains, and can be calculated to grains per 100 cub. ft. If it 
is desired to express the result in percentage by volume, 
proceed as follows: A cubic foot of dry carbonic acid 
weighs 817.3 grains, therefore dividing the number of grains 
per 100 cub. ft. by 817.3 equals the percentage by volume 
of C 0 2 present in the gas. 

Estimation of Sulphuretted Hydrogen by Cadmium 
Chloride. —A saturated solution of cadmium chloride, which 
has been slightly acidulated with hydrochloric acid is used 

G 


98 


ANALYSIS OF CRUDE COAL-GAS. 


for this test. 500 c.c. of this solution are placed in three 
Woulfe bottles, say 200 c.c. in first and second, and 100 c.c. 
in the third. 

Gas is now passed through these bottles, which are 
connected up as usual, and the presence of SH 2 is noted 
by the solution giving a yellow precipitate. When this 
precipitate arrives at the second Woulfe bottle, attention 
must be given, and directly the third bottle turns the 
slightest yellow, the test must be shut off. 

There is a blow-off cock as in similar cases to get a 
good, fresh, and average supply of gas. The gas is passed 
at the rate of about 0.5 cub. ft. per hour, and must not be 
allowed to bubble too quickly through the cadmium chloride. 
The bottles are now washed out with a little distilled 
water, to which has been added a few drops of hydrochloric 
acid ; the whole is now placed in a beaker, and an excess of 
bromine water added, or neat bromine added, to oxidise the 
cadmium sulphide to a sulphate. When completely oxidised, 
and the excess of bromine boiled off, add hydrochloric acid, 
and precipitate the sulphur by addition of barium chloride, 
which will give a white precipitate of barium sulphate. 
This is filtered, and well washed till free from chlorides, and 
incinerated in a platinum crucible and weighed as BaS 0 4 . 
The weight of BaS 0 4 multiplied by .1459 gives the weight 
of sulphuretted hydrogen in the quantity of gas taken. 

Another method for estimation of SH 2 is as follows :— 
A standard solution of iodine is made up so as to be of a 
decinormal strength, the titration being effected by a deci- 
normal sodium hyposulphite solution, starch being used 
as indicator. The following reactions take place:— 

H 2 S + I 2 = 2 HI + S. 

The test is carried out with a Wanklyn bottle (which holds 
T V of a cub. ft.). The results at the best are only very 
approximate, because undoubtedly the sulphur compounds 
other than sulphuretted hydrogen have an effect on the 
iodine causing an incalculable error. 


CYANOGEN. 


99 


Carbon Disulphide.—This compound is estimated by 
what is called the Referee sulphur test, and is given under 
that heading. 

Cyanogen.—-There are many methods on the market 
for extracting the cyanogen from coal-gas. The cyanogen 
exists in the gas in the form of hydrocyanic acid gas, and 
there is a great deal of difference of opinion as to the 
best method of arresting this important compound. 

In some works it is arrested directly after the exhausters 
or condensers by a solution of ammonium ferrosulphide 
solution ; this is made by adding a certain quantity of 
“ copperas ” or iron sulphide to a certain strength solution of 
ammonia (which is obtained by washing the gas with water), 
forming a solution of ammonium ferrosulphide solution, 
which, when the gas containing the hydrocyanic acid gas is 
washed by this solution, forms ammonium ferrocyanide. 

There are numerous other methods for extraction of the 
cyanogen from gas. Feld proposes to extract it by using 
calcium chloride and ferrous sulphate. The following 
equation expresses the result:— 

2oNH 3 + 6HCN + 7C0 2 + ioCaCl 2 + FeS 0 4 + 2oH 2 0 = 
Ca 2 Fe(CN) 6 + 2 oNH 4 C1 + 7 CaC 0 3 -t- CaS 0 4 + i3H 2 0. 

Dr J. Crossman, in December 1903, read a paper before 
the Society of Chemical Industry. The reactions upon 
which he bases his process are briefly summed up in the 
following equations:— 

(1.) 2Na 4 FeCy 6 + (3 + x )H 2 S 0 4 -= 6HCy + Na 2 Fe 2 Cy 6 + 
3Na 2 S0 4 + x H 2 S 0 4 . 

(2.) 3Na 2 Fe 2 Cy 6 + 6NaOH + 40 = 3Na 4 Fe 2 Cy 6 + Fe 3 0(3 + 4 ) 
+ 3H 2 0. 

(3.) NaOH + HCy = NaCy + H 2 0 . 

As seen, the Cy is extracted by soda, and afterwards 
decomposes with H 2 S 0 4 , &c., making either sodium cyanide 
or hydrocyanic acid liquid. 

1.0F0. 


100 


ANALYSIS OF CRUDE COAL-GAS. 


The other method of arresting the hydrocyanic acid gas 
is to allow as much as will go forward to the purifiers, 
where it enters into combination with the oxide of iron, 
forming a cyanide of iron. The method for extracting this 
from the spent oxide will be given when dealing with spent 
oxide. The drawback in this latter method is that a 
certain portion of the total HCN in the gas is lost by 
washing with the liquid in the extraction of ammonia, 
forming ammonium sulphocyanide, &c., which do not pay 
to extract the amount of cyanogen. 

In the analytical experiment for the estimation of the 
total hydrocyanic acid the method is as follows :—A 30 per 
cent, solution of caustic potash is made up by dissolving 300 
grams of caustic potash in a litre of water, and a 10 per cent, 
solution of sulphate of iron is prepared in a similar manner. 
These two solutions are now mixed in the proportion of 
4 of the potash to 1 of the iron. This is now placed in 
four small Woulfe bottles, and the gas passed through 
these, forming ferrocyanide of potassium. The test is 
stopped when the last bottle begins to turn blackish. The 
meter is read to know the quantity of gas passed. The 
bottles are washed out and mixed, and a certain portion 
taken and boiled, still free of ammonia; it is then filtered 
and the precipitate well washed. 

This solution contains certain impurities, the chief one 
being sulphur, which comes down with the Prussian blue, 
causing a considerable error. To eliminate these impurities 
acidify with hydrochloric acid, and add barium chloride, 
which precipitates the sulphur as barium sulphate, filter, and 
precipitate the cyanogen as Prussian blue, by adding an 
excess of ferric chloride, allow to stand for a little while on 
water bath, and then filter on a tared filter paper, wash 
well, dry in oven and weigh ; calculate the weight on the 
total quantity of caustic potash and iron solution used gives 
the amount of Prussian blue in the quantity of gas taken ; 
this is easily calculated to lbs. of Prussian blue per ton of 
coal carbonised. 


ESTIMATION OF PRUSSIAN BLUE. 


IOI 


In the estimation of Prussian blue care must be taken 
not to take too large a proportion of the solution as, if the 
precipitated blue is very heavy, it is very difficult to wash it 
free of excess of iron. 

The amount of Prussian blue found can easily be calcu¬ 
lated to grains of hydrocyanic acid per ioo cub. ft. 

This is far the best way of expressing the result, as it is 
shown how the cyanogen exists in the gas. 

Example — 

Gas used on experiment = 134.5 cub. ft. 
Amount of Prussian blue = 22.40 grams. 

Make of gas per ton of coal carbonised = 10,700 cub. ft. 

Therefore 22.40x10,700^134.5 = 1782.74 grams of Prussian 
blue per ton of coal. 

Thence 1782.74-^-453.6 = 3.93 lbs. Prussian blue per ton of coal 
carbonised. 

To express the lbs. of Prussian blue in grains of hydro¬ 
cyanic acid per 100 cub. ft. proceed as follows :— 

1782.74 x 15.4 = 27454.2 grains. 

27454.2 x 468 = 12848565.6 grains. 
12848565.6-^-860=14940.19 ,, 

14940.19 x 27 -r 26 = 155.32 grains HCN. 

Therefore 155.32 grains of hydrocyanic acid per 100 cub. ft., 
which is equivalent to 3.93 lbs. Prussian blue per ton of coal 
carbonised. 

The amount of Prussian blue can be estimated volu- 
metrically by a standard solution of zinc sulphate made by 
dissolving 45 grams of pure zinc sulphate in a litre of 
water. This solution is standardised by titration against a 
standard solution of potassium ferrocyanide, 5 per cent. 

1 c.c. of the ZnS 0 4 =i c.c. potassium ferrocyanide. 

1 c.c. „ „ = 0.05 gram potassium ferrocyanide. 

Multiply the numbers of c.c. of zinc sulphate solution used 
by 0.687 = Prussian blue, Fe 4 .Fe 3 Cy 18 . The indicator in this 
case is ferric chloride, and is used on the spot reaction 
paper as in the estimation of iron in bog-ore. 


CHAPTER VI. 


ANALYSIS OF LIME. 

The analysis of lime from a gas chemist’s point of view 
means the estimation of the total amount of free lime or 
caustic lime (CaO). 

The lime used in a gasworks is what is known as 
“flare” lime. This is prepared from the purest chalk, and 
the term “ flare ” is derived from the method employed in 
burning the chalk to lime. 

The flare from a furnace burns the chalk to lime as per 
the following equation :— 

CaC 0 3 + heat = CaO -f C 0 2 . 

The old-fashioned kiln method in which the fuel and chalk 
are mixed together, or else laid in a layer of fuel and then a 
layer of chalk, gives a similar result, but requires “ picking” 
afterwards to get rid of the clinker, and the lime formed is 
not so pure, as the ash of the fuel forms various calcium 
silicates. 

In the analysis of chalk, all that is required is the esti¬ 
mation of the carbon dioxide, which theoretically is 44 per 
cent, of C 0 2 , from the equation CaC 0 3 = ioo, CaO =66, and 
C 0 2 = 44. In the analysis of “flare” lime the carbon 
dioxide (C 0 2 ) and the caustic lime (CaO) are estimated. 

There are numerous methods for carrying these out on 
a works where it is only necessary to get “ approximate ” 
results to show how a kiln is working, and it is only 
required to estimate the amount of carbon dioxide to 
ascertain how the plant is going. 


scheibler’s calcimeter. 


103 

The quickest and easiest method is to estimate the C 0 2 
by some sort of calcimeter, or an apparatus known as the 
Schrotter apparatus. The figure below shows the Scheibler’s 
calcimeter. The working of the apparatus is as follows :— 
A known quantity of lime is taken (say .5 gram) and is 
put into bottle A, tube B in bottle A being filled with a 33 
per cent, solution of hydrochloric acid. The stopper is 
then closed, and the bottle turned on one side, so that the 
hydrochloric acid flows out on to the lime, the carbonic 
acid is then evolved and passes over 
into the bag c, which is inflated with 
the gas and acts on the air in the 
bottle, and so sends the water down 
the graduated arm of the burette 
with a corresponding increase in the 
other arm. The amount of decrease 
in the water is read off, and, multi¬ 
plied, gives the percentage of C 0 2 in 
the sample. This result is only ap¬ 
proximate, but very good results can 
be obtained if care is taken in keep¬ 
ing the apparatus in the same place, 
and the temperature about the same 
day by day. Of course this appa¬ 
ratus is not suitable for small per¬ 
centages of C0 2 , but anything above 
5 per cent, gives very fair results. 

In the use of the Schrotter apparatus the result is esti¬ 
mated by difference, i.e., a known weight of lime or chalk 
is taken, the C 0 2 evolved, and the flask and contents 
weighed again. Decrease in weight is C 0 2 . 

Fig. 31 shows the Schrotter apparatus. A known 
quantity of lime or chalk is weighed out and put into 
the flask at the stopper on side of flask marked A. The 
acid is admitted from the stoppered funnel C, while the 
escaping carbon dioxide is dried by its passage through the 
strong sulphuric acid contained in B. The gas passes up 



Fig. 30. 

Scheibler’s Calcimeter. 











104 ANALYSIS OF LIME. 

the central tube within B, and forces the acid down to the 
level of the holes near the bottom of the outer tube, and 
then bubbles out through the acid and escapes at the top 
of the outer tube. 

Neither of these apparatus are suitable for the esti¬ 
mation of C 0 2 in lime or chalk, if these substances contain 
any volatile matter that is evolved on the addition of 
hydrochloric acid, such as sulphuretted hydrogen, which is 

present in reburnt lime. 

The method to employ 
for accurate determination 
of carbon dioxide is by ab¬ 
sorbing the C 0 2 either in a 
Geissler’s & Mohr potash 
bulb, or in a U tube filled 
with soda lime. 

The method of procedure 
is as follows :— 

Fig. 32 represents the 
apparatus used for the pro¬ 
cess. 

The method of working is 
as follows:—1 or 2 grams of 
lime or chalk are taken and 
put into flask A; a solution 
of hydrochloric acid (33 per 
cent.) is added through safety 
funnel; the carbonic acid 
gas evolved is driven through 
the U tubes and is absorbed in G. The cupric phosphate 
tubes are only necessary when testing spent or reburnt 
lime, to retain the sulphuretted hydrogen driven off. The 
calcium chloride tubes are- weighed before and after the 
experiment, together with the Geissler bulb and drying 
tube; the increase in weight of the latter giving the 
amount of C 0 2 in the quantity taken, which can be easily 
calculated to percentages. 













ESTIMATION OF TOTAL LIME. 


105 


After describing the various methods for the estima¬ 
tion of carbon dioxide, the next estimation is for total 
lime. 

The usual quantitative method is to dissolve a weighed 
quantity, say 50 grams, in hydrochloric acid, and take an 
aliquot part of this and add alcohol (spirit of wine) in the 



Fig. 32.—Apparatus for Determining the C 0 2 . 

A is the evolution flask ; B t bulbing flask containing sulphuric acid; C, (J tube containing 
cupric phosphate; D, ditto; E and F, U tubes containing calcium chloride; and G> 
Geissler’s potash bulb, with calcium chloride tube attached. 


proportion of about two-thirds of the spirit to one-third of 
the solution. After thoroughly mixing add sulphuric acid 
in a slight excess. 

Calcium sulphate (CaSOJ is precipitated. The solution 
is then filtered, and the filter paper washed with dilute 
spirit, and eventually dried, ignited, and weighed. 





















































io 6 


ANALYSIS OF LIME. 


The calculation is then very easy from the following 
factors :— 

i grain CaS 0 4 = o.4i2 CaO. 

i ,, C 0 2 =1.272 CaO. 

1 „ C 0 2 =2.272 CaC 0 3 . 

Mr H. Leicester Grevelle, F.I.C., F.C.S., gives a most 
useful method {Journal Gas Lighting , 17th October 1905). 
It is founded on the fact that free lime, though having a 
limited solubility in water, is very much more soluble in 
strong solution of pure cane sugar or glycerine. 

His experiments were made on sugar solution. These 
were placed in a 20 oz. flask, 100 grams of the finely 
ground sample, and distilled water added to effect slaking. 
The sugar solution was then added and the mass 
digested for about half an hour at a gentle heat, the 
solution diluted and made up to a measured volume, and 
a portion titrated with standard sulphuric acid with any 
suitable indicator. He obtained concordant results with 
the CaS 0 4 method. The advantage claimed is that it is 
volumetric and only takes the free lime into account, 
rendering a special determination of the proportion of 
carbonate unnecessary. The amount of CaO in a good 
sample of flare lime should not be less than 94.0 per cent., 
and the C 0 2 not higher than 3.0 per cent. 

Another method ought to be mentioned here that 
has been tried with varying results. The method is as 
follows:—A weighed quantity of lime is slaked, dried in a 
water bath at 212 degrees Fahr., and weighed again. 
The increase in weight is water absorbed to form calcium 
hydroxide, Ca(OH) 2 . The method is as follows;—The 
sample of lime is well mixed and 10 grams are weighed 
out in a porcelain dish. Water is then added in excess 
to thoroughly slake the lime. 

The basin and contents are now placed in a water oven 
and dried until weight is constant. The increase in weight 
gives the amount of water absorbed by the lime (CaO) to 


ESTIMATION OF CALCIUM. 


107 


form the hydrate CaH 2 0 2 , as CaO +H 2 0 = CaH 2 0 2 . Now 
the water in the hydrated lime is not decomposed at 
100 degrees Cent., therefore the increase in weight gives 
the amount of water absorbed to form the hydrate. Now 
18 parts of water absorbed represent 56 parts of caustic 
lime. In this the increase in weight was 3.1, which equals 
31.0 per cent. 

Therefore 18:31 :: 56 : 95.88, 

which equals 95.88 per cent, caustic lime. 

The best gravimetric method for estimating the calcium 
oxide (CaO) in a sample of lime is as follows :— 

Weigh out 1 gram of the sample and dissolve it in a 
weak solution of hydrochloric acid, pouring the acid gently 
down the side of the beaker till all effervescence ceases. 
When it has all been dissolved that will dissolve, filter, to 
separate the undissolved matter (silica, &c.). 

The beaker should have a watch glass placed over it 
during the time it is dissolving, as on the addition of the 
acid it is liable to splash. The watch glass is then washed 
into the beaker, and to the filtrate ammonia is added until 
the solution smells strong of the reagent. The liquid is 
now heated to boiling. The calcium in the form of calcium 
oxalate is now precipitated by the addition of a slight 
excess of a warm saturated solution of ammonium oxalate, 
to which a little ammonia has been added. The beaker 
and contents are kept at the boil for a few minutes and 
then allowed to settle. The clear liquid is now decanted 
off through a filter without disturbing the precipitate. The 
precipitate is now washed three or four times in the beaker, 
by addition of distilled boiling water, and allowed to settle 
each time, and the washing poured on to the filter. The 
small quantity of precipitate poured on the filter paper at 
each washing will so far fill up the pores of the paper 
that when, after the third or fourth washing, the precipitate 
is finally poured on the filter paper the filtrate will come 
through perfectly clear. The precipitate is then washed 
with hot water until the filtrate is free from chlorides, 


io8 


ANALYSIS OF LIME. 


indicated by the absence of any milkiness on the addition 
of a few drops of silver nitrate acidifying with nitric acid. 
The filter paper and contents are now put into the water 
bath, and when dry the precipitate is transferred as 
completely as possible into a platinum crucible, the filter 
paper being incinerated separately, and the ash added to 
the precipitate in the crucible. 

The precipitate (calcium oxalate) is then converted 
into the carbonate by a gentle heat, care being taken that 
the crucible never reaches a visible redness at the bottom 
of the crucible. After gently heating for about twenty 
minutes, cool in desiccator and weigh. This gives the 
calcium oxide in the sample in the form of carbonate. 
The calcium carbonate can now be converted into calcium 
oxide by further heating the crucible for about ten minutes 
to a red heat, and finishing for a few minutes with a blow¬ 
pipe flame. Cool as before, and again weigh ; the operation 
is repeated until there is no further loss in weight. This 
gives the calcium oxide in the sample. 

The Estimation of Silica and Alumina.—The residue 
remaining after the evolution of carbonic acid, and which 
has not been dissolved by hydrochloric acid, is sand and 
clay. A small quantity of what is called soluble silica 
will be found in the hydrochloric acid solution. No 
difference is generally made in the estimation of silica, 
whether soluble or insoluble, but the total is estimated as 
follows :— 

The total contents of the flask are rinsed out into a 
porcelain dish, a little strong nitric acid added, and the 
liquor evaporated to dryness. The porcelain dish is then 
gently heated on a sand bath until all moisture is driven 
off, which is ascertained by holding a watch glass over 
porcelain dish, when no moisture should be deposited. 

The porcelain dish is now allowed to cool, and the 
contents are heated with a little strong hydrochloric acid, 
so that everything except the silica is dissolved. A little 


SEPARATION OF IRON AND ALUMINA. IO9 

water is now added, and the precipitate filtered off, the 
precipitate being well washed with water until free from 
chloride (ascertained by adding a drop of silver nitrate to 
a little of the filtrate in a test-tube, when it should remain 
clear, a slight cloudiness showing presence of chlorides). 

The residue is now dried in the water oven (paper and 
all) and next ignited in a platinum crucible. The residue 
is generally more conveniently incinerated apart from the 
filter paper, the filter paper being added to crucible after¬ 
wards. The weight of residue obtained equals silica in 
the amount taken, and can easily be calculated to per¬ 
centage. The filtrate contains the iron and alumina, which 
are in the form of their respective oxides, viz., ferric oxide, 
Fe 2 0 3 , and aluminium oxide, A 1 2 0 3 . 

These are estimated separately. 

Separation of Iron and Alumina.—A considerable 
quantity of ammonium chloride is added to the filtrate and 
gently warmed ; ammonia is now added in slight excess, 
and the mixture boiled ; this precipitates both the iron and 
alumina hydroxides. They are now filtered and washed. 
The precipitate is dissolved in the filter by pouring a little 
warm dilute hydrochloric acid, and the solution poured 
into a strong solution of potassium hydroxide (free from 
alumina) contained in a platinum dish, and the mixture is 
then boiled for two or three minutes. The iron is pre¬ 
cipitated as ferric hydroxide, the alumina remaining in 
solution as potassium aluminate. The precipitated ferric 
hydroxide is now filtered off, well washed with water, then 
re-dissolved in hydrochloric acid and re-precipitated by 
slight excess of ammonia. The ferric hydroxide is again 
filtered, washed, and dried in the usual way, and ignited 
and weighed in the form of Fe 2 O s . The total filtrates are 
acidified with strong hydrochloric acid, and the aluminium 
precipitated as hydroxide by addition of a slight excess 
of ammonia. The precipitate is washed and dried and 
ignited and weighed as A 1 2 0 3 . 


I 10 


ANALYSIS OF LIME. 


Sometimes the material contains manganese, which 
however is in very small quantities, and is not usually 
analysed separately for. 

The analysis of spent lime is very difficult, as the various 
sulphides formed are continually undergoing oxidisation, 
thereby altering their original state. It is very rare indeed 
to analyse a sample of spent lime, except for the amount 
of carbonate and sometimes for the amount of free lime 
that is left unconverted in carbonate. 

For estimation of carbonate proceed as in chalk or flare 
lime, taking care to keep back any sulphuretted hydrogen. 

For estimation of free lime, or rather hydrated as 
Ca(HO) 2 , proceed as follows :—The process consists in add¬ 
ing an excess of a solution of a copper salt to a weighed 
quantity of lime. The CaO, H 2 0 gives a precipitate of 
CuO, H 2 0 , the excess of the Cu remaining unaltered in the 
solution. Knowing how much Cu salt was first added, 
and then determining the amount remaining in solution, 
the difference between the two represents the amount of 
Cu thrown out of solution as hydrate. The equivalent of 
this quantity of CuO, H 2 0 in terms of CaO, H 2 0 is the 
amount of CaO, H 2 0 in the quantity operated on. A 
weighed quantity of spent lime is weighed out (say io grams) 
and is placed in a ioo c.c. measure, and standard cupric 
chloride solution added up to the measuring line. The 
mixture is allowed to stand a few hours, and is periodically 
shaken up. A measured quantity (say 20 c.c.) of the clear 
liquid is taken out by means of a pipette, placed in a 
suitable vessel, and an excess of NH 4 HO added — the 
blue liquid formed diluted to a convenient strength with 
distilled H 2 0 . 

NH 4 OH and distilled water are next placed in a similar 
vessel, and some of the standard cupric chloride solution 
run in, until the same depth of colour is obtained by 
looking down the liquid on to a white surface. 

Ascertaining how much of this standard cupric chloride 
solution is equal to that present in the 20 c.c. of liquid 


ca(ho) 2 in SPENT LIME. Ill 

taken, it is easy to calculate the amount equal to that in 
the whole ioo c.c. The amount of cupric chloride present 
in the original ioo c.c. being known, and that now present 
being ascertained, the difference between the two quantities 
is the amount of CuCl 2 removed as hydrated from the 
solution. Its equivalent of CaO, H 2 0 can therefore be 
calculated. 

The reaction is represented by the formula :— 

CuCl 2 , 2H 2 0 + CaH 2 0 2 = CuH 2 0 2 + CaCi 2 + 2 H 2 0 . 


CHAPTER VII. 


AMMONIA . 

The great bulk of ammonia and ammonia compounds is 
obtained from gasworks, where decided efforts are made to 
remove all the ammonia that exists in the gas by washing 
with water, which absorbs the ammonia. 

In the Forty-Second Annual Report on Alkali, &c., 
Works, by the chief inspector, published in July 1906, the 
following Table is given :— 


Recovery and Production of Ammonia. 
Amount of Sulphate of Ammonia Produced in the 
United Kingdom (Tons). 



1905. 

1904. 

1903. 

Gasworks ----- 

U 5,957 

150,208 

149,489 

Ironworks ----- 

20,376 

19,568 

19,119 

Shaleworks 

46,344 

42,486 

37,353 

Coke oven works 

30,732 

20,848 

17,438 

Producer gas and carbonising 
works (bone and coal) 

15,705 

12,880 

10,265 

Total 

269,114 

245,990 

233,664 


The most important contributor still of course remains the 
gas industry. 

The next subheads following gasworks in the Table 
show the produce from coal used in blast furnace opera- 











NITROGEN IN COAL. 


113 

tions in ironworks, and from shale used in the production 
of paraffin oil. The other items explain themselves. 

The total nitrogen in coal varies from 1 to 2 per cent., 
but in the destructive distillation of coal nothing like the 
whole of the nitrogen escapes in the form of ammonia. 
(Lunge, “ Coal-Tar and Ammonia.”) 

As early as 1863 A. W. Hofmann stated that coal in 
carbonising only yields one-third of its nitrogen, two-thirds 
remaining in the coke. Dr Tidy remarks that if all the 
nitrogen in coal reappeared as ammonia in the gas liquor, 
it would yield per ton of coal from 142 to 226 gallons 
of liquor of 4 degrees Tw., while in practice rarely more 
than 45 gallons is obtained. 

W. Foster {Jour. Chem. Soc., xliii., p. 105) showed that, 
of 100 parts of nitrogen contained in coal, there were 
obtained in a laboratory experiment:— 

T4.50 parts as ammonia, 

i-5° „ „ cyanogen, 

35.26 „ in the elementary condition (as part of coal-gas), 

48.68 „ remaining in the coke. 

Watson Smith {Jour. Soc. Chem. Ind., 1883, p. 438) found 
that coal-tar, which Foster neglected in his calculations, 
contained 1.667 P er cent. N (pitch containing 1.595, and 
coal-tar oil about 2 per cent.), that is, not quite o. 1 per 
cent. N calculated upon the coal from which the tar is 
derived. In coke he found :— 

Ordinary gas coke - - 1.375 per cent, nitrogen. 

Bee-hive coke - - - 0.511 „ „ 

Coke from Simon-Carres ovens 0.384 ,, „ 

This shows that much less nitrogen is driven out of 
coal in the short process of gasmaking than in the long- 
continued process in the manufacture of metallurgical 
coke. There are many methods for increasing the yield of 
ammonia from coal, such as adding lime, treating coal 

H 


AMMONIA. 


114 

with steam. For further information of this matter the 
reader is referred to Lunge, “Coal-Tar and Ammonia.” 

Ordinary gas liquor can be divided into two classes, 
viz., the volatile ammonia, and the fixed ammonia. The 
fixed ammonia is formed during the scrubbing or washing 
of the gas, when the ammonia enters into chemical com¬ 
bination with the carbon dioxide, sulphur, and cyanogen. 
These substances are :— 

I. Volatile at ordinary Temperatures — 

Ammonium carbonate (mono, sesqui, bi). 

„ sulphite, (NH 4 ) 2 S. 

„ hydrosulphide, NH 4 .HS. 

„ cyanide. 

„ acetate (?). 

Free ammonia. 

(The presence of free ammonia is doubted by most 
chemists.) 

II. Fixed at ordinary Temperatures — 

Ammonium sulphate. 

„ sulphite. 

„ thiosulphate (hyposulphite). 

,, thiocarbonate. 

„ chloride. 

„ thiocyanate (sulphocyanide). 

„ ferrocyanide. 

— Lunge. 


The Alkali Report for 1905, pages 35 and 36, gives the 
following analysis of samples of English gas liquor :— 




Analysis of Gasworks’ Liquor. 


Remarks. 

Gasliquor stored 

from April to 

Sept., distilled 

from Oct. to 

Mar. Inclined 

retort used for 

gas making. 

Ditto. 



Storage for six 

weeks’ make of 

liquor. 


V 

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O 

cd 




co 

CO 



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co 

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q 

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00 



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Liquor. 

No. I. (A). 
900,000 cub. 
ft. of gas 
scrubbed 
daily. 

Jan. 24, 1905. 

No. I. (B). 
250,000 cub. 
ft. of gas 
scrubbed 
daily. 

July 6, 1905. 

No. II. 

Feb. 6, 1905. 

Average 


































































































AMMONIA. 


116 



Fig. 33. 
Twaddell’s 
Hydrometer. 


The Analysis of Ammoniacal Gas 
Liquor. —This is not unfrequently carried 
out in a gasworks by means of a hydrometer, 
but generally only as a very rough guide. 

Twaddell’s hydrometer is generally used 
for this purpose, and the rule is :—Degrees 
Twaddell multiplied by 2 equal oz. of 
ammonia in liquor per gallon. 

But this process, which is really the 
specific gravity of the liquor, is most decep¬ 
tive, and is certainly in the favour of the 
buyer and against the gas company, for the 
ammonium salts raise the density of the 
solution in an unequal degree, and free am¬ 
monia (which seldom occurs) lowers it. 

This is proved by the following experi¬ 
ment, the liquor being tested by Twaddell 
hydrometer, then distilled (as explained later) 
for the total ammonia, both free and fixed :— 

Degrees on Twaddell hydrometer = 3 x 2 = 6.00 oz. 

By Will’s distillation test = 7.80 oz. 

The following Table, given in Lunge’s 
“ Coal-Tar and Ammonia,” still further proves 
the point:— 


Degrees Baume 

2° 

2 - 5 ° 

3 ° 

3 - 5 ° 

4 ° 

4 . 5 ° 

5 ° 

6° 

Specific Gravity - 

I.OI38 

1.0163 

1.0208 

1.0249 

1.0280 

1.0316 

1.0352 

1.0426 

Per cent. NH 3 - 

9 9 9 9 

9 9 99 

99 99 

9 9 9 9 

9 9 99 

99 99 

9 9 99 

9 9 9 9 

99 9 9 

9 9 99 

1.16 
1.42 
1.50 
1.77 

1.30 

i *43 

1.63 

1.77 

1.98 

2.18 

2.65 

1.63 

1.76 

1.90 

2.10 

2.38 

2.45 

1.87 

2.00 

2.24 

2.40 

2.72 

2 - 55 
2.72 
2.90 

3 - 40 

2.79 

2.85 

3.06 

3-40 

3-53 

3.67 

3-74 



































STANDARD ACID. 


II 7 

These tests, which have been proved correct by 
T. H. Davis (Chemical Nezvs , xxxviii., p. 193) and others, 
show that it is decidedly wrong to value a gas liquor by its 
gravity. It is therefore decidedly preferable to value gas 
liquor by a chemical test. 

There are two methods in use: the general one in use 
in England is to state the amount of ammonia in oz. per 
gallon. This refers to the number of ozs. of real sulphuric 
acid (H 2 S 0 4 ) required to saturate or neutralise 1 gallon 
of liquor. 

The standard acid is made by diluting 16.5 oz. of 
H 2 S 0 4 with water, and making up the total to 1 gallon. 
The specific gravity of this standard solution at various 
temperatures is as follows :— 


Temperature. 

Specific 

Gravity. 

Temperature. 

Specific 

Gravity. 

Temperature. 

Specific 

Gravity. 

Degrees Fahr. 

50 

51 

52 

53 

54 

55 

56 

1.06640 
1.06621 
r.06602 
I.06583 
I.06564 
I.06545 
I.06524 

Degrees Fahr. 

57 

58 

59 

60 

61 

62 

63 

I.06503 

I.06482 

I.06461 

I.06440 

I.06419 

I.06398 

I.06377 

Degrees Fahr. 

64 

65 

66 

67 

68 

69 

70 

I.C6356 

I.06335 

I.06314 

I.06293 

I.06272 

I.06251 

I.06230 


When the acid solution is as near as possible to the 
desired gravity, it must be tested either by titrating against 
sodium carbonate, or 10 c.c. may be precipitated with 
barium chloride, when it should yield 2.378 grams of barium 
sulphate. This solution is then run into 16 c.c. of the gas 
liquor to be tested, until it is exactly neutral, as shown by 
litmus paper, or methyl orange, or some suitable indicator. 
The number of c.c. of standard acid used gives the ozs. 
of free ammonia and ammonium salts per gallon ; this is 
generally called the acid test or saturation test, but is no 
indication of the real value of a sample of gas liquor. 

When the total ammonia, including both free and fixed, 













AMMONIA. 


118 

is required to be estimated, a known quantity of liquor is 
distilled with a solution of potash or soda in excess into a 
known quantity of standard acid. It is necessary to prepare 
a standard sodium hydrate solution to exactly equal the 
standard acid, z.<?., i c.c. of the standard acid will be exactly 
neutralised by I c.c. of the standard soda solution. There¬ 
fore as each c.c. of the standard acid used to neutralise the 
liquor equals I oz. of ammonia per gallon, the soda solution 
will therefore be of equal strength. 

The method of procedure is as follows:—16 c.c. of the 
gas liquor to be tested are placed in the flask C, excess of a 
strong solution of potash is added through funnel E, stop¬ 
cock closed, 16 c.c. of the standard acid are placed in flask 
G, and sufficient distilled water, so that the tube F will be 
submerged. The gas is now lighted, and the gas liquor 
kept boiling steadily for an hour or more, until all the 
ammonia is driven off, proved by opening cock E, and 
holding a turmeric paper there, which instantly turns red 
if any ammonia is present. 

On completion of distillation the flask G is washed out 
and titrated by the standard soda solution to ascertain how 
many c.c. of the acid solution have been neutralised by the 
ammonia in the gas liquor. 

The number of c.c. of soda solution used, deducted 
from 16 c.c. (the number of c.c. of acid used), gives the 
number of oz. per gallon of liquor. 

Example — 

16 c.c. of acid= 16 c.c. of soda. 

16 c.c. of acid used for distillation; 7.8 c.c. of soda used to 
neutralise acid solution after distilling the gas liquor. 

Therefore 16 c.c. - 7.8 c.c. = 8.20 oz. of ammonia per gallon. 

This is what is known as Will’s distillation test. (The 
other method for estimation of the percentage of ammonia 
is described under ammonium sulphate.) These are the 
usual tests carried out on a gasworks, but it is sometimes 
necessary to have a complete analysis of a gas liquor. 



Fig. 34.—Apparatus for the Estimation of Ammonia. 

, Sand bath ; B y Bunsen burner ; C, Flask for liquor ; D 9 Cork ; E , Thistle funnel ; E, Glass tube connecting C to G ; 
G , Flask containing acid ; H , Burette ; K, Alkalimeter ; /, Twaddell hydrometer and jar. 





































































120 


AMMONIA. 


The foregoing tests are from the Report of the Chief 
Inspector of Alkali Works. The complete report on 
analyses of ammoniacal liquor from various sources is con¬ 
tained in the Fortieth Annual Report, and one or two 
additions have been made in some of the subsequent ones. 


Ammonia. 


i. Free Ammonia — (A) By Direct Titration (to deter¬ 
mine approximately the volume of acid required for dis¬ 
tillation ( B )).—io c.c. of liquor are diluted to ioo c.c. and 


N 

titrated with H 2 S 0 4 —methyl orange indicator. 

(. B ) By Distillation .— io c.c. liquor (more if weak) 
diluted to about 300 c.c. in round-bottomed flask connected 
through a catch bulb to Liebig’s condenser and receiver, 
N 

containing excess of H 2 S 0 4 and provided with outlet acid 


catch packed with broken Jena glass (some beads are found 
N 

to yield alkali to — acid, and their use is not recom¬ 


mended) ; at the close of distillation air is blown through 
the apparatus to remove final traces of ammonia. 

150 c.c. of the solution are distilled, the excess of acid 


in receiver is titrated with Na 2 CO s , then 100 c.c. further 

2 N 

distilled into receiver without acid, titrated with — H 9 SCX. 

2 1 4 

The amount of ammonia obtained by this second dis¬ 
tillation is in general nil. In exceptional cases, however, 
e.g, producer gas liquors, evolution of ammonia from decom¬ 
position of nitrogenous organic matter was so continuous 
as to make it impossible to complete the distillation for 
“ free ” ammonia. 

In such cases it was only possible to present a figure 
for “total” ammonia (free and fixed), addition of caustic soda 
readily effecting the decomposition of ammonia-yielding 
compounds. 


FIXED AMMONIA. 


21 


Fixed Ammonia — (C) By Distillation. —Add boiled 
caustic solution in excess, with sufficient water to replace 
that distilled off, and proceed as above. 

The whole of the ammonia is found in the first 150 c.c. 
of distillate, with rare exceptions. In such exceptional 
cases the distillation is prolonged with addition of more 
water. 

(Attention is directed to the behaviour of cyanides on 
distilling a gas liquor containing these with caustic soda. 
It was proved that hydrocyanic acid when boiled with 
caustic soda yielded sodium formate and ammonia, as per 
the equation :— 

HCN + NaHO + H 2 0 = NH 3 + HCOoNa. 

It was also found that cyanogen compounds where decom¬ 
posed by steam resulting from oxidation of the sulphuretted 
hydrogen by air :— 

HCN + H 2 0 = NH 3 + CO. 

A reaction analogous to the formation of ammonia from 
metallic cyanides when heated with steam.) 


Calculations — 


N 


NH 3 grams per 100 c.c. of liquor = .0085 x 10 x c.c. — acid. 

H.E. (Hydrogen Equivalent) = ^ ree ^ rams . 

.017 


2. Carbonic Acid. —10 c.c. of liquor are diluted to 400 
c.c., 10 c.c. of ammoniacal calcium chloride (1 c.c. = .044 
gram C 0 2 ) added, and the whole heated in a stoppered 
bottle for one and a half to two hours in a water bath at 
100 degrees Cent. Cool somewhat, filter, wash by decanta¬ 
tion with boiling water, and dissolve the calcium carbonate 
N 

in 25 c.c. to 50 c.c. — HC 1 , with added cold water to 

prevent loss of acid. The small amount of calcium carbon¬ 
ate on the filter paper is best recovered by incineration. 



122 


AMMONIA. 


C 0 2 grams per ioo c.c. of liquor = .on x io x c.c. 



H E _ gram s 
.022 


3. Chloride.—10 c.c. of boiled liquor (for convenience 
250 c.c. are boiled, to expel sulphide, &c., cooled and made 
up to 250 c.c. for estimation of chloride, sulphocyanide, 
ferrocyanide, &c.) are diluted to 150 c.c., 20 c.c. of hydrogen 
peroxide (10 volumes free from chloride) added, and the 
solution boiled until the brown colour has almost entirely 
disappeared; 10 to 15 drops of potassium chromate solu¬ 
tion are then added to destroy the excess of peroxide and 
to aid in the removal of organic matter, and the boiling 
continued for five minutes. Filter, if necessary, from traces 
of green chromium hydrate, cool, neutralise by addition of 

a pinch of sodium bicarbonate, and titrate with — AgN 0 3 . 
Calculation — 

HC 1 grams per 100 c.c. = .00364 x 10 x c.c. — AgN 0 3 . 

10 

4. Sulphur— ( A ) As Sulphate. —250 c.c. of the liquor 
are concentrated to about to c.c. on the water bath, 2 c.c. of 
strong hydrochloric acid added, and the evaporation con¬ 
tinued to dryness to decompose thiosulphate and render 
organic matter less soluble in water. The residue is ex¬ 
tracted with water and the filtered solution made up to 
250 c.c. The sulphate is determined by precipitating 100 
c.c. of this solution with barium chloride, allowing the 
precipitate one night to settle. The amount of oxidation 
undergone by the thiosulphate under these conditions is 
insignificant. 

Calculation — 

Sulphur as sulphate, grams per 100 c.c. = 0.1373 x grams 
BaS 0 4 . 



SULPHOCYANIDE. 


123 


( B ) As Sulphocyanide .—To 50 c.c. of the boiled solu¬ 
tion (see “Chloride,” as above) add ferric chloride, in 
amount slightly in excess of that required to complete the 
precipitation of the ferrocyanide (Note .—As ferrocyanide has 
only been detected in gas liquor analysed here on very rare 
occasions, addition of ferric chloride is generally found to 
be unnecessary, and is omitted. The appearance of Prussian 
blue, however, on adding ferric chloride (slightly acid) to 
the boiled liquor is regarded as one of the best qualitative 
tests for ferrocyanide) as Prussian blue, filter (the solution 
may be warmed to promote separation of the blue in the 
flocculent condition essential for rapid filtration), cool, add 
sulphuric acid in sufficient excess, followed by copper 
sulphate, and set aside in stoppered flask for one or two 
hours in the cold to deposit the cuprous salt. Filter cold, 
wash thoroughly with hot water, using a little sodium 
sulphate in the wash water if the precipitate shows a 
tendency to pass through the filter paper; the final wash¬ 
ings must remain colourless on addition of a trace of 
ammonium sulphide. Wash the cuprous sulphocyanide, 
which should be white, back into the flask, the last traces 
being removed from the paper by warming on a clock glass 
with dilute nitric acid (1 : 3), add 1 c.c. to 2 c.c. of strong 
nitric acid, and boil the solution until green (in presence of 
much organic matter evaporation to dryness and gentle 
ignition, followed by further treatment with nitric acid, is 
sometimes required to complete the oxidation of the 
copper). Cool the oxidised liquid, add slight excess of 
sodium carbonate, acidify with acetic acid, add potassium 

N 

iodide, dilute and titrate the liberated iodine with — thio- 

10 

sulphate, using starch as indicator. 

Calculation — 

Sulphur as sulphocyanide, grams per 100 c.c. = 2 x .0032 x 
N 

c.c. — thiosulphate. 


124 


AMMONIA. 


(C) As Sulphide , Sulphite, and Thiosulphate. —(i.) ioc.c. 
of liquor are diluted to 500 c.c., acidified with hydrochloric 
N 

acid, and titrated with — iodine, starch as indicator. 

5 10 

The volume of — iodine required determines that of 
10 

the liquor taken for (2.). 

(2.) 10 c.c. of liquor, or more, are added to excess of 
ammoniacal zinc chloride solution, diluted to about 80 c.c. 
with warm water, filtered, and thoroughly washed with 
warm water (about 40 to 50 degrees Cent.). 

(a) Sulphide. —The zinc sulphide on the filter is washed 

N 

into excess of — iodine, acidified with hydrochloric acid 

(the last traces of sulphide being washed through with cold 
dilute acid) after vigorous agitation to complete the solution 
of zinc sulphide, water is added, and the excess iodine 
N 

determined with — thiosulphate. 

Calculation — 

Sulphur as sulphide, grams per 100 c.c. = 10 x .0016 x c.c. 

— iodine. 

10 

N 

H 0 S= 10 x .0017 x c.c. — iodine. 

10 

H.E = H 2 S gra ms 
.017 

(b ) Sidphite and Thiosulphate. — The conclusion is 
reached that no exact estimation of sulphite and thiosul¬ 
phate is possible in ammoniacal liquor by any method 

N 

based on titration with — iodine, except in quite excep¬ 
tional cases. 

A united figure for these two constituents can be reached 
by difference, subtracting from the total sulphur found by 
bromine oxidation the sum of the sulphurs present as 
sulphate, sulphocyanide, and sulphide. 



TOTAL SULPHUR. 


125 


(D) Total Sulphur. —50 c.c. (100 c.c. of weaker liquors) 
of liquor are delivered drop by drop from a burette into a 
flask containing excess of bromine (free from sulphur), 
covered by water, strongly acidified by hydrochloric acid ; 
the oxidised solution is evaporated to dryness on the water 
bath, the residue repeatedly extracted with boiling water, 
filtered, cooled, made up to 250 c.c., and 100 c.c. precipitated 
with barium chloride. 

Calculation — 

Sulphur grams per 100 c.c. = 5x.i373x grams BaS 0 4 . 

In the case of some liquor, eg., coke oven liquor, oxida¬ 
tion with bromine is often found to yield a heavy yellow 
precipitate of brominated phenols ; this may retain traces 
of sulphur in amount sufficient to affect the percentage 
distribution sulphur figures unless it is recovered by fusion 
with potassium carbonate and nitrate in the total. The 
correctness of the bromine oxidation method is confirmed 
later. 

(E) Sulphur as Poly sulphide. —The conclusion is reached 
that the methods of analysis elaborated so far afford no 
certain evidence of the existence of polysulphide in am- 
moniacal liquor; indeed, the known reactions of this body 
with sulphite to form thiosulphate, and with cyanide to 
form sulphocyanide, appear to exclude the possibility of its 
occurrence in ordinary ammoniacal liquor. 

The more important papers relating to the above are:— 

“ Examination of the Ammoniacal Liquor of the Gasworks,” 
by S. Dyson ( Journal , Society of Chemical Industry, 1883, pp. 229- 

23 0- 

(Note. —Dyson procedure for estimation of sulphocyanide is 
regarded as untrustworthy.) 

“Some Notes on Gas Liquor and Ammonia Purification” (in 
which methods of stating results are specially detailed), by Lewis 
T. Wright ( Journal , Society of Chemical Industry , 1886, pp. 655- 
661). 

“Laboratory Notes,” presented to the Incorporated Gas 


126 


AMMONIA. 


Institute (35th Annual Meeting), by John T. Sheard ( Journal of 
Gas Lighting , July 1898). 

“Coal-Tar and Ammonia,” by George Lunge (3rd edition, pp. 

738-755)- 

“Volumetric Analysis,” by Francis Sutton (8th edition, pp. 
78-87). 

For “ Estimation of Chloride ” see Abstract of paper by 
O. Herling ( Journal , Society of Chemical Industry, 1900, p. 336). 

“Estimation of Cyanogen Compounds,” by W. Feld {Jour, 
fur Gasbeleuchtimg, 1903, 46 (29) to (33), pp. 561-666). 


Estimation of Sulphite in Ammoniacal Liquors.— 

The difficulties attending an exact estimation of sulphite 
in ammoniacal liquor have been fully considered, in the 
hope of arriving at a reliable method. Numerous methods 
were tried, and the following adopted :— 

Poly sulphide Method .—It is a well-established fact that 
solutions of ammonium polysulphide and ammonium sul¬ 
phite react to form ammonium sulphide and ammonium 
thiosulphate, eg .:— 


(N H 4 ) 2 S 2 + (NH 4 ) 2 S 0 3 = (NH 4 ) 2 S + (N H 4 ) 2 S 2 0 3 . 

As a result of this reaction the iodine value of the 
solution is decreased by 1 c.c. — iodine for every .0032 

gram of sulphur as sulphite decomposed, the iodine value 
of the thiosulphate produced being half that of the sulphite 
reduced. This decrease affords a means, therefore, of 
calculating the amount of sulphite present. 

The procedure adopted is as follows:— 

(a) Total iodine value of solution is determined by 

titrating 10 c.c. of diluted and acidified liquor with —" 

10 

iodine. 


N . 


iodine equivalent of H 2 S + H 9 S 0 3 + H 2 S 2 O q = A c.c. 


ESTIMATION OF SULPHITE. 127 


( b ) Iodine equivalent of sulphide is determined by 
ammoniacal zinc chloride method described above. 


N . 

— iodine equivalent of H 9 S = B c.c. 

10 

N 

— iodine equivalent of H 2 S 0 3 + H 2 S 2 Q 3 = A - B. 


( c ) Iodine equivalent of half the sulphite and the thio¬ 
sulphate is determined by adding 10 c.c. of liquor to 10 c.c. 
or more of diluted polysulphide liquor (prepared by digest¬ 
ing strong ammonium sulphide solution with powdered 
sulphur, decanting; 2 c.c. of this solution freshly diluted 
to 100 c.c. gives the dilute solution used for analysis). 
After standing five to ten minutes in the cold, the clear, 
yellow liquor is precipitated by excess of ammoniacal zinc 
chloride and filtered ; the filtrate is acidified with hydro- 

N 

chloric acid and titrated with — iodine. 

10 


— iodine (less iodine for thiosulphate contained in the 

polysulphide used) is the equivalent of JH 2 S 0 3 + H 2 S 2 0 3 . 
Two examples will make this clear. 

1. Coke Oven Liquor :— 

N 

10 c.c. liquor H 2 S + H 2 S 0 3 + H 2 S 2 0 3 = 8.57 c.c. — iodine A. 

,, 1 ^ 2 ^ = 7 - 7 1 >> 


h 2 so 3 +h 2 s 2 o 3 
jh 2 so 3 + h 2 s 2 o 3 

jh 2 so 3 


= 0.86 


A-B. 


= 0.60 (thiosulphate in 
polysulphide 
deducted) C. 
= 0.26 „ A - (B + C). 


Whence 


Sulphur as sulphide= 10 x .0016 x 7.71 =.1234 gram of sulphur 
per 100 c.c. 

Sulphur as sulphite = ic x .0016 x 2 x .26 = .0083 gram of sulphur 
per 100 c.c. 

Sulphur as thiosulphate = 10 x .0064 x .34 = .0218 gram of sulphur 
per 100 c.c. 


128 


AMMONIA. 


2. Gas Liquor (cyanide present, hence polysulphide 
presumably absent):— 


io c.c. liquor H 2 S + H 2 S 0 3 4-H 2 S 2 0 3 = 32.13 
» H 2 S =30.71 


H 2 S 0 3 + H 9 S 2 0 3 
JH 2 S 0 3 + h 2 s 2 o 3 

jh 2 so 3 


= 1.42 
= 1*33 


A. 

B. 

A-B. 

C. 


= .09 A —(B + C). 


Whence 


Sulphur as sulphide = 10 x .0016 x 30.71 = .4914 gram. 

„ sulphite = 10 x .0016 x 2 x .09 = .0029 gram. 

Sulphite, if present, only exists in this liquor in an in¬ 
significant amount. It is reasonable to conclude that it 
is absent. It should be pointed out that the iodine figure 
for JH 2 S 0 3 is reached by subtraction = A —(B + C). This 
will eliminate, to a material extent, the effect due to inter¬ 
ference of organic matter, as titrations A and C are carried 
out under very similar conditions, while B is not considered 
to be materially affected under the conditions observed for 
the precipitation of the zinc sulphide. 

Careful experiments were also made on mixtures con¬ 
taining various known proportions of sulphite and thio¬ 
sulphate, both in presence and absence of organic matter, 
to determine the limitations of this method. 

The results obtained are shown in the accompanying 
Table, which, it is hoped, is sufficiently clearly set out to 
save detailed explanation. 

In experiments Nos. 7 and 8 the results of analysis 
clearly indicate absence of sulphite in the solution examined. 
In experiments Nos. 1 to 6 the amount of sulphite found in 
each case is in satisfactory agreement with that taken. 


DISTRIBUTION OF SULPHUR IN AMMONIACAL LIQUORS. 1 29 


Estimation of Sulphite by Polysulphide Method. 
(Per too c.c.) 



O g .. 

Taken—! 

Sulphur, 

, Grams. 

Found— 

-Sulphur, Grams. 

Liquor. 

3 B >> 

Cv 

* T! c 

V 

JO 

6 « 

As Sulphite. 

6 

JO 

(-! 

.2 ^ 

V 

43 


Sulphui 
sulphi 
for A 

As Sulpl 

H'a, 

<i 

Present. 

Added. 

Total. 

a* 

"3 
c n 

< 

IS c« 

& ~ 

< 3 

_Q. 

3 

cn 

< 

A. Organic matter 
absent. 

No. 1 - 

grams. 

.0429 

absent 

absent 

.0156 


.0156 



•0153 

No. 2 - 

.0286 

9 9 

.0384 

.OIO4 

... 

.OIO4 

... 

.0392 

.0102 

B. Organic matter 
present. 

Coke oven liquor— 
June 23, No. 3 - 

.071S 






.1234 

.0218 

.OO83 

With added sul¬ 
phite, No. 4 - 

.0715 

.1234 

.0218 

.0083 

.0262 

•0345 

.1202 

.0282 

.0304 

June 24, No. 5 - 

•0715 

... 

• . . 

. . . 


. . . 

.1218 

.0198 

.0075 

With added sul¬ 
phite, No. 6 - 

.0715 

.1218 

.0198 

.OO75 

.0259 

•0334 

. 1206 

.0269 

.0301 

Polysulphide 
added to re¬ 
move sulphite, 
No. 7 - 

•0715 

.1368 

.0413 

absent 


absent 

.1362 

.0378 

.OOIO 

Gas liquor (oxidised 
by partial expo¬ 
sure to air, 20 
months), No. 8 - 

.2145 

absent 


... 

... 

absent 

.2204 

-.0003 


* Exclusive of that reacting as sulphide. 


Distribution of Sulphur in Ammoniacal Liquors. —If 

we subtract from the total sulphur found by bromine 
oxidation the sum of the constituent sulphurs found as 
sulphate, sulphocyanide, “thiosulphate” (determined by 
titration of the acidified filtrate from the sulphide by 
N 

— iodine), and sulphide, a difference in figure is obtained, 

which has proved to be invariably negative in sign, since 
the adoption of the improved method of estimating sulpho¬ 
cyanide described above. 

I 























130 


AMMONIA. 


Evidence was previously obtained that some of the 
difference noticed was due to the presence of sulphite, 
which caused the “thiosulphate” figure to largely exceed 
its proper value by reason of the factor for conversion of 

~ iodine into sulphur as thiosulphate being .0064 gram 

sulphur per 1 c.c. ~ iodine, while that for sulphite is only 

one-fourth of this. This has failed, however, to reduce the 
difference figure to the limits of reasonable experimental 
error, and the conclusion is reached, therefore, that organic 
matter is the disturbing cause, as such differences are not 
noticed when the same methods are applied to determine 
the same constituent in solutions from which organic 
matter is excluded. 

Various considerations point to the thiosulphate titra¬ 
tion as the one peculiarly liable to such interference; for 
this reason the iodine method of estimating this constituent 
in ammoniacal liquors is finally rejected in favour of a 
figure arithmetically obtained by difference. 

Estimation of Cyanogen Compounds in Ammoniacal 
Liquor. —In ammoniacal liquor three cyanogen compounds 
alone are of technical interest: cyanide (hydrocyanic acid), 
ferrocyanide, and thiocyanate (sulphocyanide). 

In these analyses the “ total cyanogen ” contents of any 
given liquor is taken to be the sum of the hydrocyanic 
acid (HCy) equivalents, grams per 100 c.c. of the cyanide, 
ferrocyanide, and thiocyanate present; and the “cyanogen 
distribution ” figure for each of the compounds named to 
be the hydrocyanic acid equivalent of the compound per 
100 parts of “total cyanogen ” (as HCy) present. The 
methods are:— 

Cyanide (Hydi'ocyanic Acid). —Feld’s method for the 
estimation of ammonium cyanide is based upon the fact 
that if alkaline cyanides are distilled with a solution of mag¬ 
nesium chloride, or lead nitrate, the cyanogen is expelled 


CYANOGEN COMPOUNDS IN AMMONIACAL LIQUOR. 131 


quantitatively as hydrocyanic acid. If sulphide be present 
in the solution to be distilled, lead nitrate should be used 
to avoid the evolution of sulphuretted hydrogen which 
occurs when magnesium chloride is employed. 

The reaction when lead nitrate is used may be repre¬ 
sented by the equation :— 

Pb(N 0 3 ) 2 + 2NH 4 CN + 2H 2 0 = Pb(OH) 2 + 2 NH 4 N 0 3 + 2HCN. 

In applying this method for the estimation of hydro¬ 
cyanic acid, it has been found convenient to employ the 
apparatus used for determination of ammonia, both free 
and fixed. This consists of a 500 c.c. round-bottomed 
flask provided with two-holed caoutchouc stopper with inlet 
tube sealed in liquor, and exit tube connected through a 
catch bulb to Liebig’s condenser and receiver. 

It is safer, in distilling off hydrocyanic acid, to seal 

N 

exit tube of the condenser in the 2 K c.c. of — caustic soda, 

1 

with which the receiver is charged, a precaution quite un¬ 
necessary when ammonia is being estimated. 

Example — 

50 c.c. of liquor are distilled with excess of a 20 per cent. 

solution of lead nitrate (50 to 100 c.c.) into 25 c.c. of — soda 

for twenty-five minutes, the distillate diluted to about 400 c.c., a 
crystal of potassium iodide (about 0.2 gram) added, and the solution 
N 

titrated on — silver nitrate:— 

10 

(1 c.c. =-.0054 gram HCN) 

— AgNOg^fi^o c.c. 

Whence 

HCN per 100 c.c. liquor = 2 x 6.30 x .0054 = .068 gram. 

068 

Hydrogen equivalent (H.E.) = '—-=2.5. 


32 


AMMONIA. 


Ferrocyanide .—Feld estimates this compound by boiling 
it in alkaline solution with mercuric chloride, whereby 
mercuric cyanide is formed ; the latter body is then de¬ 
composed with sulphuric or hydrochloric acid, the hydro¬ 
cyanic acid liberated, being distilled off, and titrated with 
silver nitrate as mentioned above. Magnesium chloride is 
added to the alkaline solution before addition of mercuric 
chloride, to prevent precipitation of mercuric oxide. The 
reaction in the case of ammonium ferrocyanide may be 
represented as follows :— 

2 (NH 4 ) 4 FeCy 6 + SHgCl 2 + 3 Mg(OH) 2 
= 6HgCy 2 + Hg 2 Cl 2 + Fe 2 (OH) 6 + 3 MgCl 2 + 8 NH 4 C 1 . 

The distillation of the mercuric cyanide is conveniently 
carried out in the same apparatus as that employed for 
the estimation of hydrocyanic acid (as above), procedure, 
as regards the collection and titration of the evolved hydro¬ 
cyanic acid, being in both cases identical. The use of the 
same apparatus for estimation of “free” and “fixed” 
ammonia, hydrocyanic acid, and ferrocyanide is an advan¬ 
tage much appreciated in the complete examination of 
ammoniacal liquors, where analyses have to be promptly 
made to minimise the changes in composition that rapidly 
follow on exposure to the air. 

The volume of liquor taken is 250 c.c. Solution is 
boiled to expel volatile salts, a moderate excess (10 to 15 
c.c.) of 6 N. caustic soda added (amount calculated from 
the “fixed” ammonia found), and the boiling continued 
for a further period of fifteen minutes to remove fixed 
ammonia, and bring separated ammonium ferrous ferro¬ 
cyanide into solution. Cool, make up to 250 c.c. 

To 50 c.c. of the solution diluted to 100 to 150 c.c., and 
raised to boiling, add 5 c.c. of 6 N. soda (NaOH) followed 
by 30 c.c. of 3 N. magnesium chloride (add slowly to avoid 
formation of clots), boil for five minutes, add 25 to 50 c.c. 

of a boiling solution of — mercuric chloride, and continue 


ESTIMATION OF FERROCVANIDE. 


133 


the boiling for not more than ten minutes. The liquor is 
then distilled for twenty minutes with 30 c.c. of 6 N. 

sulphuric acid into 25 c.c. of — caustic soda. To the 

2 

distillate add a pinch of lead carbonate, and filter off the 
precipitated lead sulphide, dilute to about 400 c.c., add a 

crystal of potassium iodide and titrate on — AgN 0 3 

(1 c.c. = .0054 gram HCy). 

The presence of ferrocyanide in ammoniacal liquor is 
so uncertain that it is desirable to identify it by qualita¬ 
tive test before embarking on the somewhat lengthy pro¬ 
cedure described above. For this purpose it is sufficient 
to add to the acidified boiled liquor a drop of dilute ferric 
chloride and gently warm. 

(The boiled liquor sometimes contains small traces of 
separated ammonium ferrous ferrocyanide; it must therefore 
be well shaken before applying the Prussian blue test for 
ferrocyaqide. Addition of peroxide of hydrogen to the 
boiled liquor in such cases produces a blue body by 
oxidation.) 

If ferrocyanide is present the red colour of the thio¬ 
cyanate changes to blue, and in cases where sufficient is 
present, a flocculent blue precipitate separates. 

Thiocyanate ( Sulphocyanide )— (A) Ferrocyanide absent. 
—If qualitative test (ferric chloride to acidified boiled liquor 
and warming) indicates that ferrocyanide is absent, add 
to 50 to 100 c.c. of the boiled liquor acid sulphite of 
soda containing free sulphurous acid in excess, followed by 
copper sulphate, and set aside in closed flask for one and a 
half to two hours in a warm place (25 to 30 degrees Cent.) 
to deposit the cuprous salt. This procedure ensures separa¬ 
tion of the cuprous thiocyanate in a form readily retained 
on filtration through any good filter paper suitable for use 
with barium sulphate precipitate. Filter, wash thoroughly 
with hot water; the final washing must remain colourless 
on addition of a drop of dilute potassium ferrocyanide, or 


134 


AMMONIA. 


ammonium sulphide. Wash the cuprous thiocyanate, 
which should be white (grey if organic matter is present), 
into a platinum dish, the last traces being removed by 
warming the filter paper on a clock glass with dilute nitric 
acid (i : 3), add 1 c.c. of strong nitric acid, and evaporate to 
dryness on the water bath. The residue is gently ignited 
to remove organic matter, moistened with nitric acid, and 
again cautiously ignited to expel oxides of nitrogen ; dis¬ 
solve in dilute sulphuric acid (normal strength is suitable), 
slight excess of carbonate or bicarbonate of soda added, 
and the separated carbonate dissolved in acetic acid. To 
the clear green solution of the acetate add excess of potas- 

N 

sium iodide, and titrate the liberated iodine with — thio- 

10 

sulphate, using starch indicator (added towards the end of 
the titration). In general, the reaction proceeds a little 
sluggishly at the finish. Addition of thiosulphate should 
be added until the blue colour ceases to return after the 
solution has stood for a minute. It is more satisfactory to 


add a slight excess of thiosulphate and bring back with 
N 10 

— iodine. For technical purposes, evaporation of the 

cuprous salt to dryness with nitric acid may be omitted 
as an unnecessary refinement. In this case the cuprous salt 
should be washed back into the flask and oxidised therein 
by boiling for fifteen to twenty minutes with 2 c.c. of 
concentrated nitric acid. The free acid is then neutralised 
by sodium carbonate, and the solution prepared for titration 


on 


thiosulphate in the manner described above. 


Results so obtained are approximately accurate, but 
the complete oxidation of the cuprous salt appears to be 
somewhat difficult to complete in the case of some liquors, 
and, in addition, the end point is less easy to determine 
with certainty when nitrates and organic compounds are 
both present. Thus :— 


FERROCYANIDE PRESENT. 


35 


Organic matter absent— 

Thiocyanate taken ----- 10.00 — c.c. 

io 

Found (i) Nitric acid solution evaporated 

to dryness, &c. - - - - 9.98 c.c. 

(2) Nitric acid solution boiled 15 to 20 

minutes.9.98 „ 

Organic matter present— 

Coke oven liquor—Thiocyanate found, grams sulphur per 
too c.c. 

(1) Nitric acid solution evaporated to f(a) .0260 \ , 

dryness, &c. - - - - \ (b) .0269 J'° 2 4 

(2) Nitric acid solution boiled 15 to 20 minutes .0278 


Oxidation of the dried cuprous thiocyanate by direct 
ignition, followed by treatment with nitric acid in platinum 
dish, is inadmissible; considerable traces of copper appear 
to be volatilised on ignition of the precipitate in contact 
with filter paper. Thus :— 

Organic matter absent— 


Thiocyanate taken - 

„ found by ignition 
method - 


I (a ).0139 
\ (b) .0142 


Grams 

Sulphur. 

.Ol6o 
> .OI4O 


Loss =12 
per cent. 


Organic matter present— 

Thiocyanate found, grams sulphur per 100 c.c. 

(1) Nitric acid solution evaporated to \ 

dryness, &c. _ .0683 ( Loss = 7 

(2) Precipitate ignited to oxide, then ( per cent. 

evaporated with HN 0 3 , &c. - .0632 ) 


(B) Ferrocyanide present .—To remove the ferrocyanide, 
add to the slightly acidified boiled liquor sufficient excess 
of ferric chloride solution to render it decidedly red (ferric 
thiocyanate) and warm gently (40 to 50 degrees Cent.) 
to render the “Prussian blue” flocculent; filter. To 
the filtrate, cooled, add acid sulphite of soda containing 
free sulphurous acid and proceed as described in (A). * 


136 


AMMONIA. 


This procedure ensures the separation of the whole of 
the ferrocyanide. If desired, the “ Prussian blue ” thus 
obtained can be used for the approximate estimation of 
ferrocyanide in the gas liquor by treatment with caustic 
soda and distillation by Feld’s method. Thus :— 

Ferrocyanide, calculated as HCy, grams per ioo c.c. 

Gasworks Coke Oven 

(1) Feld’s method applied direct to Liquor. Liquor. 

boiled liquor - - - 0.172 .0065 

(2) Feld’s method applied to “Prussian 

blue” separated by ferric chloride 0.161 .0065 

The conversion of sulphide into thiosulphate is already 
well known, but the conversion of hydrocyanic acid into 
thiocyanate in presence of ammonium sulphide is of equal 
importance, but less widely known. A single example 
will serve to illustrate the point. Thus, a sample of coke 
oven liquor was examined as received, and again after ex¬ 
posure to an equal volume of air in stoppered bottle for 
fifty-eight days, with the following results :— 



When 

Opened. 

After 58 days’ 
Exposure to Air. 

Cyanide, grams HCy per 100 c.c. 

•053 

.024 - .029 

Thiocyanate, grams HCy per 100 c.c. 

.002 

.026 + .024 

Ferrocyanide, grams HCy per 100 c.c. 

nil 

nil 


•°55 

.050 


Allowing for slight loss of hydrocyanic acid by volati¬ 
lisation into the air above the liquor, we see that 50 per 
cent, of the cyanide has been converted into thiocyanate by 
simple contact with air in the cold ; a corresponding con¬ 
version of “free” ammonia ((NH 4 ) 2 S) into “fixed” am¬ 
monia (NH 4 CyS) has accompanied the change. The 
reaction doubtless proceeds on the lines :— 

(NH 4 ) 2 S.S + NH 4 Cy = (NH 4 ) 2 S + N H 4 CyS, 

the polysulphide being itself obtained by direct oxidation 
of ammonium sulphide. 


REACTION OF CYANIDE AND POLYSULPHIDE. 137 


Cyanide and polysulphide, therefore, react to form thio¬ 
cyanate, and excess of either body implies absence of the 
other. This fact accounts for the absence of polysulphide 
from gasworks and coke oven liquors, where excess of 
cyanide is generally present. 


CHAPTER VIII. 


ANALYSIS OF OXIDE OF IRON. 

In the analytical valuation of a natural oxide of iron, or 
bog-ore, it is necessary to estimate the moisture, the organic 
matter or peat, the ferric oxide, and silicious matter. These 
analyses are all comparatively simple, with the exception 
of the ferric oxide ; this, as will be explained later, is the 
most important compound in the material, and it is not 
only necessary to know the amount of ferric oxide, but to 
know the exact state this exists in the bog-ore. 

What is wanted in a good bog-ore for gas purification 
is that the ferric oxide should be in a hydrated state. There 
is no doubt that there is more than one compound of 
hydration of oxide of iron in a bog-ore, and it would be as 
well to give here the known compounds, viz.:— 

Gothite, Fe 2 0 3 , H 2 0 . 

Limonite, 2Fe 2 0 3 , 3H 2 0. 

Xonthosiderade, Fe 2 0 3 , 2H 2 0. 

Bog-ore, Fe 2 0 3 , 3HX). 

Exactly how many or how few of these hydrated com¬ 
pounds of iron exist in a bog-ore has never been definitely 
settled. It is the usual method to calculate it as all existing 
in the one form, viz., Fe 2 0 3 , 3 H 2 0 . It is really immaterial 
which is taken, so long as a definite arrangement is arrived 
at, so that there can be no disputes. 

There are three known oxides of iron, and these are:— 

1. Ferrous oxide, FeO. 

2. Ferric oxide, Fe 2 0 3 . 

3. Ferroso-ferric oxide, or magnetic oxide, Fe 3 0 4 = Fe 0 , 

Fe 2 0 3 . 


MOISTURE. 


139 


Of these, the only one that is supposed to exist in a 
natural bog-ore is the ferric oxide, although at times one 
comes across a sample that certainly contains some other 
oxide of iron, which is not the ferric oxide. 

In a chemical analysis on ah oxide it is most difficult to 
ascertain in which form the oxide exists, and it is general 
to assume it to exist as Fe 2 O s , but it is also necessary to 
know whether this oxide is in the proper state of hydration, 
and the only method to adopt is to submit the sample to a 
practical test, viz., foul it. This will certainly show the 
quality of the oxide, and whether the material is suitable 
for purification. We will now proceed to the analysis of a 
sample of oxide. 

Moisture. —The sample is well mixed and ground in a 
mortar ; 10 grams are weighed out into a counterpoise 
platinum crucible or basin. This is then put into a water 
oven which is kept at 212 degrees Fahr. (100 degrees Cent.) 
for twenty-four hours. The crucible and contents are 
weighed again, and then replaced in the oven again for a 
further period of six hours, and then reweighed. If there 
is no decrease in weight the amount of loss represents the 
water in sample ; if there is a further loss the operation 
must be repeated until no further loss takes place. 


Crucible .... 

- 

46.907 grams. 

Oxide - 

- 

10.000 ,, 

Total 


5 6 - 9°7 

Weight after drying for 24 hours - 

- 

5 2 - i8 5 » 



4.722 grams. 


Weight after drying for a further period 

of 6 hours.52.183 „ 


4.724 grams. 

After this the weight was constant. 

Therefore the sample contains 4.724 x 10 = 47.24 per cent, of 
water at 212 degrees Fahr. 



140 ANALYSIS OF OXIDE OF IRON. 

Organic Matter. —The crucible and contents from the 
above are now ignited in a muffle furnace, and it is desirable 
to always have the same method, so as to have uniformity 
in the results. The loss in weight is organic matter and 
combined water. 

Example — 

Weight of crucible from— 

Last experiment - - - - 52.183 grams. 

After ignition ----- 50.423 „ 

1.760 grams. 

Organic matter (peat) and combined water = 17.60 per cent. 

Ferric Oxide. —The residue, after organic matter has 
been burnt off, is now dissolved in boiling HC 1 acid (50 
per cent, solution) until all the ferric oxide is dissolved, 
judged by the residue being free from colour. 

The solution is then diluted and filtered, the insoluble 
residue and filter paper being afterwards ignited and 
weighed, which gives us the percentage of silicious matter. 

The filtrate is then treated as follows for the ferric 
oxide (there are numerous methods for the estimation of 
the ferric oxide, but the two principal ones will only be 
described here):— 

(1.) A portion of the filtrate is taken and precipitated 
while hot with NaOH, to eliminate the alumina present ; 
the precipitated ferric hydrate is filtered and washed with 
hot water; the ferric hydrate is redissolved in hydrochloric 
acid, and reprecipitated with N H 3 . This is filtered, washed 
with hot water, ignited, and weighed. 

The ignition must be made with the cover on the 
platinum crucible, as during the transition of the ferric 
hydrate to anhydrous ferric oxide a certain loss will be 
occasioned by “ decrepitation,” i.e., a certain portion of the 
precipitate will be projected from crucible and lost. The 
crucible and contents are now placed in a desiccator to cool, 
and weighed. 



FERRIC OXIDE. 


141 

The increase in weight from first weight of crucible 
gives the amount of ferric oxide in the amount of liquor 
taken. 

Example — 

Filtrate and washing made up to 500 c.c. 

.'. 500 c.c. = 10 grams of material. 

50 c.c. = 1 gram of material. 

25 c.c. = 0.5 „ 

25 c.c. are taken and precipitated with NaOH, &c. 
Crucible - 46.907 

Crucible + residue - - 47.071 


.164 gram Fe 2 0 3 in 0.5 gram. 
200 

32.800 Fe 2 0 3 . 

Now 160 parts of Fe 2 0 3 give 214 part of Fe 2 0 3 , 3H 2 0 ; 
therefore having obtained the percentage of Fe 2 O s , multiply 
by 1.3375 will give the percentage of Fe 2 0 3 , 3H 2 0. 

32.80 x 1.3375 = 43.86 per cent. Fe 2 0 3 , 3 H 2 °* 

(2.) By titrating with a standard solution of potassium 
dichromate. This solution is made by exactly weighing 
4.9 1 3 grams of pure potassium dichromate (previously 
dried by being gently fused in a porcelain crucible and 
then finely powdered in a dry mortar), dissolved in water 
in a litre flask, and then the solution made up to 1000 c.c. 
with distilled water at 60 degrees Fahr. (or 15 degrees Cent.). 

One litre of this — solution contains one-tenth of an 
10 

equivalent of available oxygen in grams, z>., 0.8 gram ; 
therefore 1 c.c. = 0.008 gram of available oxygen, and is 

N 

therefore equivalent to 0.0056 Fe. Therefore the — 

potassium dichromate solution is as follows :— 

1 c.c. = .0056 Fe. 

1 c.c. = .0072 FeO. 

1 c.c. = .008 Fe 2 0 3 . 

1 c.c. = .0089 Fe 2 0 3 , H 2 0 . 

1 c.c. = .0107 Fe 2 0 3 , 3H 2 0. 




142 


ANALYSIS OF OXIDE OF IRON. 


The potassium dichromate solution is stable, and has 
no action on rubber. This solution must be “ standardised,” 
that is, its exact strength must be definitely ascertained ; 
this is carried out by dissolving pure iron wire in dilute 
sulphuric acid, with the exclusion of air, in the apparatus 
shown in Fig. 35. 

Take 0.5 gram of the fine iron wire used for binding 
flowers (which contains 99.6 per cent. Fe). About 100 c.c. 
of dilute sulphuric acid (1 in 5) are placed in the flask 
(which should have a capacity of about 250 c.c.), fitted 

with a rubber cork and 
bent glass tube as shown 
in figure. The air in the 
flask is expelled by re¬ 
moving cork and dropping 
in two or three crystals of 
pure sodium carbonate; 
this expels all air, and as 
soon as the carbonate has 
dissolved, drop in the 
weighed quantity of iron. 
The cork is instantly in¬ 
serted, and is as shown in 
figure, the bent tube dip¬ 
ping into a solution of 
sodium carbonate con¬ 
tained in the beaker. The 
flask is gently heated by a small flame until the whole of 
the iron is dissolved. The gas is then withdrawn, and 
the flask allowed to cool. As the flask cools, the sodium 
carbonate solution contained in the beaker is drawn up 
into the flask. Directly the first drop enters the flask an 
effervescence of carbon dioxide is caused, which drives 
the liquid down again, at the same time filling the flask 
with C 0 2 . 

When it has partially cooled in this water the cork is 
withdrawn, and air-free distilled water added ; the flask is 



Fig. 35. —Apparatus for Dissolving 
Iron Ores. 























To face page 14J . 





FERRIC OXIDE. 


143 


then closed by a rubber stopper, and is held in a stream of 
cold water until quite cold ; transfer to a 250 c.c. flask, 
measure it, and make up to the exact quantity with further 
addition of cold air-free water. 50 c.c. of this solution are 
then taken by means of a pipette and titrated with the di¬ 
chromate solution, gradually added from a burette. The 
end of the reaction is ascertained by means of a freshly 
made solution of potassium ferricyanide used as in¬ 
dicator. 

Drop reaction paper is cut into strips about 1 in. by J in., 
on this is put a little of the ferricyanide solution by means 
of a glass rod, and some of the iron solution put on the 
paper in the same way, so that when it spreads, it meets 
the ferricyanide and causes a blue line ; but as the amount 
of ferrous salt is diminished by the gradual addition of the 
dichromate, the blue becomes less and less until finally 
the last drop so tested fails to give a blue colour. The 
tints shown in the Plate represent the gradual falling off 
in blue colour. 

Example — 

0.5 gram of iron dissolved in 250 c.c. 

0.1 „ „ in 50 c.c. 

As the wire only contains 99.6 of iron, to find the exact 
weight multiply by 996. 

Therefore 50 c.c. contain 0.0996 gram of iron. In titration 
it was found that 17.6 c.c. were used in the 50 c.c. 

Therefore 17.6 x 5 = 88.0 x .996 = 87.56 c.c., and instead of 
the solution containing 0.5 gram in 250 c.c., it only contains 
0.488 gram. 

Therefore 0.488-*■ 87.56 = .005584 instead of .0056 Fe. 

Therefore the solution is slightly weaker than it should be, 
this is easily overcome by the use of a factor. 

Having ascertained the exact strength of the decinormal 
solution it is now ready for use on the oxide of iron. 

Proceed exactly in the same way as with the iron 
sulphate solution, but there is no need to wait for the same 
sample as was used for moisture, &c., but a fresh quantity 


144 


ANALYSIS OF OXIDE OF IRON. 


may be weighed, say 2 grams, dissolved in hydrochloric 
acid, in the flask as before. When all the iron has dissolved, 
filter, add a few pieces of pure granulated zinc, and boil 
until all the Fe 2 0 3 is reduced to FeO, which is shown by 
the solution going perfectly white, filter off the zinc, and 
make up to a definite volume. 

A portion of this is then titrated with the potassium 
dichromate solution. 


Example — 

2 grams dissolved in hydrochloric acid, reduced by zinc, and 
made up to 400 c.c. 


200 c.c. = 1 gram. 

200 c.c. titrated with potassium dichromate; they required 


41.0 c.c. 

N 

1 c.c. — dichromate = .008 Fe 9 O q : 

10 2 

.008 x 41 x 2 = .656 gram Fe 2 0 3 , 

.656 x 50 = 32.80 per cent. Fe 2 O s ; 
or, 

N . 

1 c.c. — dichromate = .0107 Fe 2 0 3 , 3H 2 0; 


.0107 x 41 x 2 = .8774 gram Fe 2 0 3 , 3H 2 0, 
.8774x50 = 43.87 per cent. Fe 2 0 3 , 3 H 2 0 . 


The insoluble residue, after dissolving the iron out, 
is now burnt off in a platinum crucible and weighed. 
Increase in weight = Si 0 3 , A 1 2 0 3 , and inert matter. 

Example — 

Weight of crucible + insoluble residue - 47.143 
Crucible ------ 46.907 


.236 

.236 x 10 = 2.36 per cent, silica, alumina, &c. 

We have now a complete analysis of a sample of oxide 
of iron, which is as follows :— 



ANALYSIS OF OXIDE OF IRON. 


H5 


Summary - 


Moisture ------ 

47.24 per cent. 

Fe 2 0 3 ------ 

32.8° 

Organic matter, peat, and combined 


water ----- 

17.60 „ 

Silica, alumina, and inert matter- 

2.36 


100.00 


The Fe 2 0 3 = 32.80 per cent, expressed as being in the 
form of Fe 2 0 3 , 3H 2 0 = 43.86 per cent. 

It is usual to give the Fe 2 O s , 3 H 2 0 on the dry basis so 
that all analyses of various samples containing varying 
proportions of water are comparable. 

The method of working from wet to dry basis is as 
follows:— 

Example — 

100.00 deduct 47.24 per cent, for water. 

47.24 

52.76 equals dry material in 100 parts. 

Therefore 52.76 contains 32.80 parts of Fe 2 0 3 or 43.86 parts 
of Fe 2 0 3 , 3H0O. 

52.76 : 32.80 : : 100 : 62.16. 

Therefore Fe 2 0 3 on dry basis is 62.16 per cent. 

Therefore Fe 2 0 3 , 3H 2 (3 on dry basis is 82.92 per cent. 

Having arrived at the analysis of this sample of oxide, 
it is now necessary to ascertain that the ferric oxide Fe 2 0 3 
is in the proper state of hydration for the necessary 
chemical reaction that takes place in the purifiers, where 
the hydrate ferric oxide absorbs the sulphuretted hydrogen 
in the gas according to the following formula :— 

Fe 2 0 3 , 3 H 2 0 + 3H 2 S = Fe 2 S 3 + 6 H 2 0 ; 
or when revivification takes place in situ : — 

Fe 2 0 3 , 3 H 2 0 + 3 H 2 S + 3 0 = Fe 2 0 3 , 3 H 2 0 + 3 S 4 - 3 H 2 0 . 

K 




46 


ANALYSIS OF OXIDE OF IRON. 


Now in the analytical valuation of a bog-ore it is practi¬ 
cally impossible to give any idea as to its value as a purify¬ 
ing reagent, i.e., the ferric oxide may exist as a hydrate, or 
it may not, or in the analysis other oxides of iron may be 
estimated and expressed as existing in a state of hydration, 
which they do not. To form an exact idea what state the 
ferric oxide is in, the sample is subjected to an experi¬ 
mental fouling. 

The method is as follows :—3 or 4 lbs. of the sample are 
taken and well mixed. A long 
glass cylinder (see Fig. 36) is now 
filled with the oxide, and crude gas 
is passed through it for twenty-four 
hours. The cylinder is now dis¬ 
connected and put out in a porce¬ 
lain tray or on a piece of wood and 
allowed to revivify, which usually 
takes from twenty to thirty hours. 
This is again made moisture and 
treated exactly the same as if on 
the large scale, and put into the 
cylinder and again subjected to 
the action of crude gas on the 
inlet to purifiers (the same place 
as before) for twenty-four hours 
when it is again revivified. 

This operation is repeated till 
the sample fails to show any appreciable absorbing of 
sulphur, usually in about eight foulings. 

A sample is taken from each fouling, the moisture is 
estimated, and the sulphur absorbed is extracted as in the 
valuation of spent oxide. I have found most excellent 
results by this method, especially if one has a standard to 
go by. 

Take a sample of oxide that has been used on the 
works and one of which the fouling or absorbing abilities 
for sulphuretted hydrogen is known, and try it in this 



Fig. 36.—Cylinders for Oxide 
or Weldon Mud Foulings. 








Percentage of Sulphur Abscro^J 


ANALYSIS OF OXIDE OF IRON. 


147 


























































































































































































































































148 


ANALYSIS OF OXIDE OF IRON. 


way. You will then have a standard by which you can 
compare any sample sent in, and if care is taken in the 
whole operation the result will be a most excellent criterion 
as to the suitability of an oxide for gas purification. The 
amount of sulphur absorbed is expressed in percentages on 
the dry basis. 

The accompanying curves show the standard and 
sample, which are practically similar. In this method, one 
is able to form an opinion on any sample of oxide, and to 
know for certain what a given oxide is capable of doing 
when under actual practical working conditions. 

In cases where the gas company require a high 
standard of ferric hydrate (Fe 2 0 3 , 3 H 2 0 ), it is sometimes 
the practice to add various iron ores to the sample and 
bulk which are not hydrates, and which would require 
some considerable period before they would assume that 
state of hydration which would make them profitable to 
use in gas manufacture for the purification of gas from 
sulphuretted hydrogen. This addition is made because it 
is invariably the practice to estimate the total iron as ferric 
oxide, and to calculate all this as being in the form of the 
hydrate (Fe 2 O s , 3H0O). 

To estimate the amount of ferrous oxide (FeO) pro¬ 
ceed exactly as in the method described for the standardis¬ 
ing of the dichromate solution, taking very great care 
that no air is allowed to come into contact with the 
sample, else some of the FeO will be oxidised to Fe 2 0 3 , 
which will be estimated as FeO. Directly the sample is 
cool titrate with the bichromate solution, and if there is 
any, say for example 4 c.c. are used, this number of c.c. 
must be deducted from the total number of c.c. used in 
the reduction of the total iron as Fe 2 0 3 , 4X 2 = 8 c.c., there¬ 
fore this 8 c.c. must be deducted from the 82 c.c. mentioned 
before. 

To estimate the total silica the method mentioned in 
the analysis of lime is used. 

Having now described the usual method used in the 


HYDRATES OF IRON. 


149 


analysis of an oxide, it would be advisable here to draw 
attention to numerous experiments carried out by myself, 
some of which have been confirmed by Mr Leicester 
Greville, and described in the Journal of Gas Lighting , 
14th September 1905. 

It was desired to ascertain for certain which was the 
correct formula for representing the hydrated ferric oxide 
either by the formula Fe 2 0 3 , H 2 0 , or by the formula 
Fe 2 0 3 , 3 H 2 0 . 10 grams of the natural oxide which had 

previously shown good results by fouling were weighed out 
into a platinum dish. This was then put into a desiccator 
and constantly weighed until the weight was constant, 
showing that all the free moisture was absorbed by the 
sulphuric acid in the desiccator. The loss in weight was 
40.37 per cent. The sample was then dried in the 
water oven at 100 degrees Cent. (212 degrees Fahr.) 
until the weight was constant; this gave a loss of 11.84 
per cent. 

Now the formula Fe 2 0 3 , H 2 0 theoretically requires 10.11 
per cent, of moisture. This practically proves that the mono¬ 
hydrate of iron, Fe 2 0 3 , H 2 0 exists in the sample. 

The sample was next placed in a combustion tube con¬ 
nected on to a calcium chloride tube which had been pre¬ 
viously weighed, and the combined water which did not 
come off at 212 degrees Fahr. driven off together with the 
organic matter. This was weighed and showed 7.18 
per cent, of combined water, and 23.42 per cent, organic 
matter. 

To arrive at the exact amount of combined water the 
calcium chloride tube was connected up as before, and dry 
coal-gas passed through it which carried the combined 
water into another weighed calcium chloride tube. Now 
the combined water being 7.18 per cent., and the nearest 
hydrated oxide that we have to this is 2Fe 2 0 3 , 2H 2 0, which 
requires 10. n per cent, of moisture. 

Now the various hydrated oxides with the percentage of 
water theoretically required are :— 


ANALYSIS OF OXIDE OF IRON. 


150 


Fe 2 0 3 , H 2 0 = 10. i r per cent, of water. 

2Fe 2 0 3 , 2H 2 0= io.n ,, „ 

2Fe 2 0 3 , 3H 2 0= 14.40 „ 

Fe 2 0 3 , 3H 2 0= 25.22 „ „ 

The method used was as follows :—The hydrate of iron 

having the formula Fe 2 0 3 , H 2 0 requires 10.43 P er cent. 
Fe 2 0 3 to combine with it, and therefore as our water loss 
over sulphuric acid during desiccation may be taken as 
representing this hydrate, we shall require 10.43 P er cent, 
of our total Fe 2 0 3 to combine with the water found, and 
10.43 — 32.80 (our total Fe as Fe 2 0 3 ) will leave us 22.37 
per cent. Fe 2 0 3 . 

Now the combined water above 212 degrees Fahr. was 
found to be 7.18 per cent. We are justified in taking this 
as existing in the hydrate of 2 Fe 2 0 3 , 2 H 2 0 (although some 
may exist as the other two hydrated oxides), and the 
Fe 2 0 3 required to give the formula 2 Fe 2 0 3 , 2 H 2 0 requires 
7.10 per cent. Fe 2 O s ; we have 7.10 —22.37 per cent., leaving 
15.27 per cent, of Fe 2 O s which we may call “unattached,” 
or which exists in the sample as free Fe 2 0 3 unhydrated. 

Other samples of well-known bog-ore confirm this 
result, although in some cases the “ unattached ” Fe 2 0 3 is 
very low, being as low as 1 to 2 per cent. 

These experiments prove that there is more than one of 
the hydrates of iron present in a bog-ore. Undoubtedly 
the organic matter plays an important part; this organic 
matter is of an acid nature, and it is found that when 
ammonia (only a trace) is allowed to go forward into the 
purifiers they do better work, owing to the fact that the 
acid bases in the oxide are neutralised. 


CHAPTER IX. 


NAPHTHALENE . 

BEFORE giving the various methods, &c., which have been 
tried to remove this compound, the methods for testing for 
it will first be considered. There are only two methods 
which have met with any amount of success, the first being 
that discovered by Dr Colman and J. F. Smith, and which 
is known as Colman and Smith Naphthalene Test, the 
second being that known as Dickenson-Gair’s Test. 

i. Colman and Smith Naphthalene Test — This 
method was explained in a paper read by Dr Harold 
Colman before the Society of Chemical Industry in January 
1900. 

A solution of picric acid which is nearly saturated at 
normal temperature, and which is about normal. The 
strength of this solution is accurately determined by 
N . . 

titration with -j— soda solution, using lacmoid as indicator, 

the colour of which is changed from brownish yellow to 
green on a slight excess of alkali. 

The apparatus consists of a series of five bottles, the 
first having a capacity of 4 oz., the second of 10 oz., the 
other three being of 2 oz. capacity each. They are charged 
as follows :—The first with a solution of citric acid which 
serves to remove any ammonia in the gas, the second 
contains 100 c.c. of the picric acid solution, the third and 
fourth 25 c.c. each of the same solution, whilst the fifth 
bottle serves to retain any splashing that may be carried 


52 


NAPHTHALENE. 


forward. The fifth bottle is connected to the meter. The 
various bottles are connected preferably with metallic 
flexible tubing, as ordinary rubber tubing absorbs naph¬ 
thalene when new; if rubber tubing is used, the glass ends 
of the bottles must be brought as close together as possible, 
so that the gas comes in contact with the rubber as little 
as possible. The gas is now passed through the bottles at 
the rate of from 0.5 to 1.0 cub. ft. per hour until 10 cub. ft. 
have passed ; the contents of the smaller bottles are washed 
into the 10-oz. bottle, using as little water as possible, as 



naphthalene picrate is soluble in water. An indiarubber 
cork fitted with a glass tube at the bottom and having a 
small hole in the side is then lightly inserted in the bottle, 
the hole in the tube being just below the bottom of the 
stopper, and the air in the bottle evacuated with the water 
pump as completely as possible. 

While the pump is still working, the glass tube is drawn 
up so that the side hole is well within the rubber stopper, 
the bottle being thus sealed. The bottle is now discon¬ 
nected from water pump and placed in a water bath, and 
boiled. The boiling is continued, with occasional shaking of 
























































NAPHTHALENE TEST. 


53 


the bottle, until the solution of naphthalene picrate is quite 
clear, or until all the free naphthalene has combined with 
the picric acid forming naphthalene picrate. 

When absolutely clear the bottle is removed from water 
bath and is now allowed to cool. During cooling the 
bottle must be occasionally shaken to prevent free naph¬ 
thalene settling out on the side of the bottle. After the 
bottle has become quite cold, the whole of the naphthalene 
picrate will crystallise out in fine needle-shaped crystals. 

The contents of the bottle are washed into a 250 c.c. 
flask, the latter filled up to the mark with water, and 
thoroughly shaken and filtered. The first few c.c. of the 
filtrate are rejected, as, owing to the filter paper absorbing 
some of the picric acid, they are weaker than the rest. 

100 c.c. of the rest of the filtrate are now taken, and 0.5 
c.c. of the lacmoid solution added, and titrated with the 
standard soda solution until the colour changes to the 
characteristic green. The 50 c.c. burette supplied with this 
apparatus is specially graduated on one side, the uncor¬ 
rected number of grains of naphthalene per 100 cub. ft. is 
read off direct, but only when the above-mentioned 
quantities and strengths of solution and volume of gas 
passed (10 cub. ft.) are adhered to. The reading thus 
obtained divided by tabular number gives the corrected 
number of grains of naphthalene per 100 cub. ft. 

The meter supplied with this test is so arranged that it 
can be used in cases where the pressure is not sufficient to 
drive the gas through the bottles. In this case the water 
pump is connected with the tube A on the outer meter 
case and the water turned on. Air or gas is then drawn 
from the space between the meter and the outer case with 
which the meter outlet is in open connection, and as the 
vacuum rises., the mercury level rises in the right-hand 
limb of the tube B and falls in the left-hand limb, this con¬ 
tinuing until the level in the latter falls below the bottom 
of the tube C. As soon as this happens, air is drawn into 
the meter case through the side tube D, so that the vacuum 


154 


NAPHTHALENE. 


cannot rise higher. The amount of vacuum is regulated 
by varying the height of the tube C, and must be fixed so 
that the gas is drawn through the bottles at the desired 
rate. The bottle E is interposed to catch any globules of 
mercury which may be carried over with the current 
of air. 

In finding the tabular for correction to N.T.P., the 
amount of vacuum shown on the mercury gauge must be 
deducted from the height of the barometer, as this repre¬ 
sents the difference between the pressure under which the 
gas is registered and that of the atmosphere. The facts 
and reasons of this test are—naphthalene combined with 
the picric acid forming naphthalene picrate, which has 
the formula C 10 H 8 , C 6 H 3 N 3 0 7 , with free naphthalene, hence 
the necessity to boil the solution, so that the free naphtha¬ 
lene will be taken up, forming naphthalene picrate, which 
is an alkali. 

It is necessary to remove the ammonia by citric acid, 
or some other suitable solvent, because this would tend to 
reduce the acidity of the picric acid, causing an error. The 
above apparatus is only for use when the strength of the 
picric acid solution is exactly ^ normal; this is not always 
easy to obtain, so the following information will be useful 
to those who either have not the apparatus or else cannot 
get the picric acid solution to the desired strength. 

Titrate the picric acid solution first with — caustic 

IO 

soda, i c.c. of which = 0.0229 gram of picric acid. 
After passing gas, boiling, &c., titrate again with ^ 
caustic soda. 

The formula for naphthalene picrate is C 10 H S , C 6 H 3 N 3 0 7 , 
229 parts of picric acid are united with 128 parts of 
naphthalene, and therefore the quantity of picric acid 
128 

found X ~ °-559 gives the quantity of naphthalene in 
the volume of gas used for test. 


EXAMPLE OF NAPHTHALENE TEST. 


T 55 


Exaniple- 


N 


150 c.c. of picric required 74 c.c. of — soda. 

10 

74 

.0229 


666 

148 

148 


1 6cu6 f § ram pi cr i c acid before passing 
| gas through. 

The picric acid afterwards required 67.8 c.c. 

Therefore 67.8 x .0229 = 1.55262 gram of picric acid after 


gram of picric acid lost as naph¬ 
thalene picrate. 


passing gas. 

1 1.6946 

i-55 2 6 

.1420 j 
•559 1 

12780 

7100 

7100 

7 g J g ram °f naphthalene in quantity 
•°7937 0 | 0 f g as passed. 

.079378 x 15.43 — 1.2248 grain in quantity of gas passed. 

Quantity of gas at N.T.P. = 10.31 cub. ft. 

Therefore 1.2248 -r 10.31 x 100 = 11.879 grains of naphthalene 
per 100 cub. ft. 


2. Dickenson-Gair’s Modification of Colman and 
Smith Naphthalene Test. —This method was described 
by Mr C. J. Dickenson-Gair before the Chemical Industry 
in December 1905. The author of this process uses acetic 
acid of a specific gravity of about 1.044. 

About 350 c.c. of this acid are taken and put in two 
bottles (as in Colman test). A small WoulfPs bottle con¬ 
taining 150 c.c. of picric acid solution is also added after 
the acetic acid to act as a catch, and a measured volume of 







56 


NAPHTHALENE. 


gas not more than 3 to 6 cub. ft. passed through at the 
rate of i cub. ft. per hour. The ammonia is removed by 
a suitable solvent. After the experiment is finished the 
acetic acid and picric acid from the bottles are mixed in 
a flask, and about 500 c.c. of concentrated picric acid 
solution added. Pure naphthalene picrate separates out at 
once in large flocculent masses, which have the advantage 
of being easily filtered. 

After filtering, the naphthalene picrate is dried in vacuo 
or a warm room and weighed. 

This method gives practically identical results as with 
Colman and Smith method, and the same apparatus is 
suitable for its use. 

There is yet one other method worthy of notice, i.e., 
one devised by Somerville :—Three glass tubes about 7 in. 
long and 1 in. in width are fitted up in a similar manner 
to bottles used in other tests, and about 35 c.c. of 70 per 
cent, of alcohol are poured into each. The three are 
closely connected, a measured quantity of gas passed 
through, and the test disconnected. The contents of the 
tubes are then washed out and intimately mixed in a 
flask. 

If the gas used is impure, it will be necessary to add 
concentrated oxalic acid solution until the ammonia is 
entirely neutralised, as shown by litmus paper. The con¬ 
tents of the flask are now filtered and the filter paper 
washed with dilute alcohol. 

Concentrated picric acid is added in large excess— 
about 500 c.c. are generally necessary—the liquid agitated 
and allowed to stand for half an hour. By that time all 
naphthalene picrate will have separated out, and may 
be filtered, dried slowly, and weighed. The amount of 
naphthalene found in the gas varies tremendously, both 
owing to the class of coal used, temperature of carbonisa¬ 
tion, method of taking tar off in the hydraulic main, 
&c. &c. 


REMOVAL OF NAPHTHALENE. 


157 


The usual amount found is as follows :— 


Before condensing, gas 
After condensing, gas 
Outlet of purifier 
Outlet of works 


about 80 grains per 100 cub. ft. 
)} 1 5 » J> 

»> IO „ » 

J) 7 5 ) 


In this case no naphthalene extractor was at work, the 
only naphthalene that is extracted being that which was 
condensed out by condensers, washers, purifiers, &c., but 
no special effort was made to remove this bye-product. 

Many and various have been the methods devised to 
remove naphthalene from coal-gas. Some have met with 
success, and others have not come up to or done what was 
expected of them. 

As far as experiments and expert opinion have arrived 
at the present time, these can be divided into two 
sections :— 

1. Those whose aim and object is to relieve the gas 
of naphthalene by condensation, and the use of various 
vapours in the gas to absorb the naphthalene and prevent 
it from coming down in the crystalline form ; and 

2. Those whose object is to wash the gas with some 
solvent of naphthalene, generally a coal-tar oil which 
absorbs the naphthalene from the gas by bubbling the 
gas through this solvent, and, when saturated, having fresh 
oil, &c. 

These methods will be considered separately. 

In the early days of gas manufacture naphthalene gave 
a good deal of trouble. We read in Bowditch, “ Analysis 
and Use of Coal-Gas,” 1867, of the trouble caused by 
deposition of naphthalene. Bowditch points out that there 
is practically an unlimited power or use in condensation, 
and says it is in the power of most engineers to make 
considerable difference in their illuminating power how 
they use or what method they adopt for condensing 
their gas. 

The proper object of condensation is the removal from 


158 


NAPHTHALENE. 


the gas of substances produced in the destructive distilla¬ 
tion of coal, which for some reason or other are not useful 
for the purpose of illumination, or which cannot be dis¬ 
tributed, but all substances which are useful as illuminants 
and can be distributed with the gas should be retained. 
He proposed, in order to accomplish this, that the hydraulic 
main be kept hot, and that the gas and vapours from 
this should be passed to a special apparatus kept at a 
regulated temperature, in which the gas and light hydro¬ 
carbons might be separated from the heavier bodies before 
passing the gas to the purifying plant, so that a larger 
proportion of the hydrocarbon vapours might be distri¬ 
buted with the gas. This method of condensation he con¬ 
siders would probably lessen the deposition of naphthalene 
in the gas, &c. 

The nearest approach we have to this is the more 
advanced and scientific method of Dr Colman’s “Cyclone” 
method. In this process the trouble caused by water 
vapour is greatly diminished by separation of the heavier 
tar fogs and liquor and gas before it reaches the condenser, 
therefore increasing the vapour tension of the lighter hydro¬ 
carbons and allowing them to exert their solvent action 
more fully on the naphthalene present. In this process 
the aim is first to remove any substance that causes the 
lowering of the vapour tension of the more useful con¬ 
stituents, so that they may have fuller play of their 
natural tendency to absorb naphthalene, and that later on 
in the operation when they are condensed the naphthalene 
will come down dissolved in the condensed matter. There 
are, one might say, two distinct ideas predominating in the 
efforts to remove naphthalene, viz., (i) where the object is to 
utilise the solvent action of the tar either during condensing 
or before, (2) to use some sort of absorbent for the naphtha¬ 
lene, such as Young and Glover’s process, Bell, Colson, &c. 

The ideas have been briefly mentioned, but a brief 
review of some of the more successful methods on these 
lines may be advantageously given : — 


REMOVAL OF NAPHTHALENE. 


59 


Mr C. E. Botley, Engineer of Hastings Gas Works, 
employs what might be called an intermediary process, 
the oil being introduced in the form of minute atoms, 
which are carried along with the moving gas, and apparently 
hold up the naphthalene. Anyhow it was definitely proved 
at Hastings that this fog was carried two miles or more 
from the works, and if these atoms of oil could be carried 
to the end of the district, Mr Botley claims that naphthalene 
troubles would cease. 

The next idea of mark is C. Carpenter’s reversible con¬ 
densers {Journal of Gas Lightings 19th Nov. 1901). Some six 
years prior to this paper Mr C. Carpenter brought forward 
the idea for the removal of the surplus naphthalene contained 
in crude coal-gas by means of a reversible condenser, in 
which the deposit naphthalene thrown down upon the water- 
cooled walls was dissolved by the hot tarry vapours of 
the foul main gas, and run off through suitable seals into 
the tar well. The condenser used was an old one ; it pos¬ 
sessed, however, two qualifications which were considered 
important, i.e. y it was vertical and water-cooled. In order 
to effect the reversing of the current of gas, and make this 
flow from left to right, or right to left, as desired, a special 
four-way valve was fitted up. The experiments on this 
apparatus proved successful, but apparatus too small, and 
Mr Carpenter adopted the following:—The new condenser 
had capacity of 2 million cub. ft. per diem ; it was decided 
to adhere to water as the cooling medium in order to render 
the reduction of temperature as far as possible independent 
of atmospheric conditions. The vertical type was also 
adopted, as a result of the satisfactory working of the 
experimental apparatus, the facility which the vertical 
afforded for the “ buttery ” naphthalene to slide down to 
the seal pots, and the further advantage that the drainage 
of these more or less liquid products was independent of the 
direction in which the gas was flowing in the apparatus. 

The following is a description of the apparatus 
used :—It consists of two rows of seven steel pipes, 


i6o 


NAPHTHALENE. 


27 feet long, formed into a horseshoe by a bridge piece 
connection at one end. Within each of these pipes are 
sixteen 2-in. tubes, running from top to bottom, screwed 
into the bottom diaphragm separating the water and gas 
spaces. The expansion of these tubes under the extremes 
of temperature worked is about J inch, and the top ends, 
therefore, after reduction in size to save friction, and also 
to distribute the flow of water, work through stuffing boxes 
carried in the upper diaphragm. The working gas valves 
consist of two pairs of ordinary slide valves, each pair 
geared together—one open, one shut—by means of a shaft 
which carries two pinions operating the racks of the valve 
in opposite directions. Two pairs of water valves are also 
provided, but these work independently. Each pair of the 
vertical condensing pipes drain into a double seal pot. 
The consistency of the dissolved naphthalene is such that, 
in order to maintain it sufficiently fluid, hot liquor must 
be continually running through the pipe, which forms the 
centre of the seal, and this precaution has been found 
essential even during the heat of summer. Valves are pro¬ 
vided to each seal so as to give access thereto in case of 
stoppage, the condenser being worked under pressure on 
the exhauster outlet. 

The condenser had been at work some six months, 
and since that time hardly a flake of naphthalene crystal 
had been seen on the works or outlet main. The meter 
overflow, which used to choke every few days, had remained 
clear, and so on throughout the plant. 

Naphthalene test on the outlet gas at station meter 
showed from i|- to 3J grains naphthalene per 100 cub. ft. 

The next paper on the subject is by Dr H. G. Colman 
(appearing in the Journal of Gas Lighting for 3rd June 
1902). Attention is confined in this paper to the separation 
of the tar vapours from the gas, without consideration of 
the condensation of the aqueous vapour, beyond stating 
the view that its influence on the removal of naphthalene, 
and the subsequent illuminating power of the gas, is only 


REMOVAL OF NAPHTHALENE. l6l 

of subsidiary importance, as water does not dissolve, and 
is not dissolved by the tar constituents to any considerable 
extent, and its separation therefore takes place practically 
as it would if no tarry vapours were present. The aim of 
condensation may be defined as the reduction of the gas 
to the atmospheric temperature, and the simultaneous 
removal, as completely as possible, of all substances which 
are not permanent gases at that temperature, with the 
exception of the lowest boiling hydrocarbons (practically 
benzene and toluene). Of these latter, it is desired to 
keep in the gas the maximum quantity it is capable of 
retaining at the lowest temperature to which it may be 
exposed during distillation. 

The idea in this paper was to separate the removal of 
the heavy tar as soon as possible, and by keeping the gas 
in contact with the light oil or tar fog containing minute 
globules of light oil as long as possible. 

The chief action is attributed to the action of the tar 
fog ; the conveying of the gas through a great length of 
foul main at a slow speed is favourable, inasmuch as it 
allows the condensation of much heavy tar which would 
otherwise have reached the condensers, but the continuance 
in the condensers of slow cooling is not advantageous, 
inasmuch as owing to the low velocity of the gas, and the 
longer time it is passing through the condensers, the light 
oil fog is largely deposited and removed from further action 
on the gas before it reaches the cold end of the condenser, 
where its solvent power for naphthalene is greatest. 

Hence, if these views are correct, it follows that, while 
slow condensation up to a certain point is desirable, the 
rate of cooling at the later stages must be sufficiently rapid 
to carry the light oil fog formed at the inlet to outlet of 
condensers. It is most important that the heavy tars have 
been previously removed. If this is not the case quick 
condensation will not effect the sufficient removal of naph¬ 
thalene, but will also bring about the absorption of benzene 
vapour, which would otherwise have remained in the gas, 

L 


62 


NAPHTHALENE. 


thereby decreasing the illuminating power. The mere 
lowering of the temperature of the gas from 75 to 60 degrees 
in the absence of solvents cannot, however, be expected to 
effect much in the naphthalene, inasmuch as the quantity 
present in the gas which has only been cooled to 75 degrees 
is less in many cases than is necessary to saturate it at 60 
degrees. The points to be considered are (1) the complete 
removal of the heavy tar fog before the condenser ; and (2) 
ensuring the presence of a sufficient quantity of light oil 
fog in the colder portions of the condenser. The first point, 
the object is in part obtained by employing long foul 
mains of ample size, but even when this is done, the gas 
at the inlet of condenser still contains a fairly dense fog. 
With the view of replacing these miles of main Dr Colman 
employed a centrifugal separator modelled on the lines of 
the well-known “ Cyclone ” dust collector. The gas enters 
through a pipe of oblong section at a tangent, thus bringing 
about a rapid circular motion of the gas in the cone. Any 
solid or liquid particles are driven by centrifugal force to 
the circumference, and fall to the bottom, where they are 
taken off direct to a seal pot. The outlet is at the centre 
of the cone, so that the gas is drawn off at the point where 
it is freed from suspended particles. The velocity of the 
gas is controlled by a flap-valve at the inlet of cone. 

The next process is the washing of the gas by solvents, 
which absorb the naphthalene in the gas. There are two 
or three different ideas as to the most suitable solvent for 
this purpose. Messrs Young and Glover took out a patent 
in 1897 for washing gas with oil for the removal of naph¬ 
thalene, and were undoubtedly the pioneers who first put 
this method before the gas industry. Since then both 
Mr Coulson, of Leicester, and Mr F. Bell, of Derby, have 
obtained success or freedom from naphthalene troubles by 
washing gas with some solvent oil. 

In July 1904, Mr Coulson, of Leicester, took out a patent 
on these lines :— 

My invention consists in an improved solvent liquid 


COULSON AND BELL’S PROCESS. 163 

capable of removing naphthalene with certainty from illu¬ 
minating gas obtained by distillation, and in a method of 
preparing this liquid. 

The raw material employed is coal-tar, or in general 
any tar. Such tar is distilled as usual, and that portion 
that comes over below 270 degrees Cent, is then further dis¬ 
tilled to isolate the mixed oils, chiefly those having a boiling 
point between 170 and 215 degrees Cent., and which contain 
only a small quantity of naphthalene. 

The oil thus obtained is capable of extracting naphtha¬ 
lene from the gas rapidly and with certainty. The density 
of the oil thus prepared is from 994 to 998, or even a little 
heavier. 

The washing of the gas is best carried out in some form 
of washer. 

Mr Coulson found that it required 0.08 gallon of the 
solvent per 1,000 cub. ft. of gas. 

This process has met with complete success in Leicester, 
completely removing all troubles caused by naphthalene 
deposits. 

Mr Bell’s process is on similar lines, but his is a dual 
process, as he first washes his hot gas with hot tar, and 
then with heavy naphtha. He also claims complete 
success. 

These various processes are given as an indication of 
the trend of opinion on how to remove the naphthalene 
nuisance, but up to the present there does not appear to be 
any universal solvent or method that will cure naphthalene 
troubles in any town, for it is apparent that the process 
that meets with success in one place may fail altogether in 
another district. 


CHAPTER X. 


THE ANALYSIS OF FIRE-BRICKS AND 
FIRE-CLA Y. 

FIRE-CLAYS are clays which are capable of standing a 
very high temperature without fusing. Such clays are 
said to be refractory. 

The composition of fire-clay varies, however ; the follow¬ 
ing Table gives the average analyses :— 


Components. 


2 

3 

4 

5 

6 

7 

Silica 

62.35 

56.42 

67.50 

73 -27 

71.97 

96.25 

65.10 

Alumina - 

18.47 

26.35 

22.39 

21.62 

24.20 

1.00 


Ferric oxide 

4-77 

i -33 

6.37 

4.24 

1.80 

i*i 5 

1.92 

Lime 

Oxide of man¬ 

trace 

0.60 

i -55 

0.58 

0.224 

1.07 

0.14 

ganese - 

. . . 

. . . 

0.44 

trace 

0.76 

Nil . 

... 

Magnesia 
Sodium - 

1.36 

°-55 

trace 

) 

trace 

0.096 

... 

0.18 

Potash 

2.47 

0.48 

| 1.30 

0.29 

0.950 

o -53 

... 

Organic matter 
Combined 

M 

... 



... 

... 

0.58 

water - 

1 \ 

10.95 

. . . 

• • . 


. . • 

7.10 

Moisture - 

4.15 

2.80 


. . . 


... 

2.18 

Titanic acid 

1.10 

1 -1 5 


... 

... 

... 

... 

Fire resistant - 
Fusible con¬ 

... 

... 

89.89 

94.89 

96.17 

97.25 

... 

stituent 

... 


10.16 

5 -i 1 

3.83 

2.75 

... 


99.89 

100.63 

100.05 

100.00 

100.00 

100.00 

99.42 


I. Derbyshire fire-clay (Riley). 2. Glenboig fire-clay (Riley). 3. Fire¬ 
brick, bad quality. 4. Retort made in Stourbridge not satisfactory owing to 
iron. 5. A fire-brick of satisfactory quality. 6. Silica brick of satisfactory 
quality. 7. Stourbridge clay. 






















ANALYSIS OF FIRE-CLAY. 


65 


A good refractory fire-clay will contain nearly pure 
hydrated silicate of alumina. The more alumina that a 
fire-clay contains in proportion to the silica, the more 
refractory will be that clay. 

On a careful observation of these analyses, it will be 
seen that the fire-resisting constituents are silica, alumina, 
and that any heavy proportion of oxide of iron, or alkalies, 
act as a flux and cause fusion ; the clay is no longer 
refractory. 

The Method of Analysis. —A quantity of the sub¬ 
stance (fire-clay or fire-brick) is reduced to an impalpable 
powder in an agate mortar. It is absolutely necessary, in 
order to ensure the complete decomposition of the silicate, 
that the powder should be so fine that there should be no 
grittiness to the touch when it is rubbed between the 
thumb and finger. The whole sample when thus ground 
should pass through a sieve of fine muslin. 

About 5 grams of the sample are dried in a platinum 
crucible or dish at a temperature of ioo degrees Cent, in a 
water bath until the weight is constant; the loss in weight 
gives the moisture. 

In the case of a clay it is ignited at first gently, and 
then placed in the combustion furnace for a tolerably long 
time. The loss in weight gives the combined water, organic 
matter, and volatile constituents of the clay, if such are 
present. 

Silica (Si 0 2 ).—2 grams of the finely powdered sample 
(dried) are weighed out in a fairly large platinum crucible, 
and about six times its weight of fusion mixture added 
(sodium and potassium carbonate mixed in molecular 
proportions). The whole is intimately mixed by means of 
a smooth rounded glass rod. The mixture should only 
half fill the crucible. The lid is then placed on the 
crucible, and the latter is then heated gently over a Bunsen 
flame, the temperature is gradually increased, great care 


166 ANALYSIS OF FIRE-BRICKS AND FIRE-CLAY. 

being taken that no loss ensues by the frothing due to the 
evolution of carbon dioxide. When the mass is fused, 
it is then heated by means of the blow-pipe, the heat¬ 
ing is continued until all effervescence ceases, and. the 
contents of the crucible are in a state of quiet fusion. 
When this is finished the crucible is allowed to cool down, 
and when cold it is placed on its side in a beaker with 
about ioo c.c. of cold water, great care being taken that no 
impurities are conveyed into the solution upon the outside 
of the crucible. The beaker is heated on a sand bath until 
the “ fusion ” is detached from the crucible. Hydrochloric 
acid is now gently added in small quantities at a time 
(the watch glass being replaced between each addition), 
until effervescence ceases, and no further precipitate of 
gelatinous mass takes place. The crucible and lid are now 
withdrawn with platinum-tipped tongs and rinsed into 
beaker. 

The mixture is now transferred to a platinum dish and 
evaporated to dryness upon a steam bath, the gelatinous 
mass being stirred at frequent intervals with a round glass 
rod to prevent the formation of lumps. In order to expel 
the last trace of HC1, the dish is transferred to an air 
bath and heated to about 160 degrees Cent, for half an 
hour. The residue is then moistened with a little HCI, and 
is then heated on a water bath for about half an hour, more 
HCI being added as evaporation takes place. Hot water 
is added and the silica is filtered off, and is washed free 
from dissolved chlorides. 

The precipitated silica is dried in the oven ; it is then 
ignited apart from the filter, the precipitate being trans¬ 
ferred to the platinum crucible very cautiously, as, since 
it consists of a very light powder, it is easily blown 
away. The covered crucible is at first heated very 
cautiously, and afterwards to a red heat, and weighed 
until constant. 


Alumina (A 1 2 0 3 ) and Ferric Oxide (Fe 2 O s ).—The 


CALCIUM AND MAGNESIUM. 


67 


iron and alumina are precipitated together in the form of 
hydroxide by the addition of ammonium chloride and 
ammonia to the filtrate from the silica. They are separated 
as under. 

The precipitate is washed and dissolved upon the filter 
with hot dilute HC 1 , and the solution allowed to flow into 
a porcelain or platinum dish, which contains about 50 c.c. 
of pure strong KOH solution. The filter paper is washed 
with a small quantity of distilled water, and these washings 
are allowed to run into dish. 

The iron will be precipitated as ferric hydrate, while 
the hydrate of aluminium will remain in solution. The 
precipitated iron is filtered off and redissolved in HC 1 , and 
reprecipitated by NH 4 OH to free it from potash. It is 
then washed, dried, and ignited apart from the filter at a 
red heat, and weighed as Fe 2 0 3 . 

The solution of aluminium hydrate in the potassium 
hydrate solution is treated with a slight excess of HC1, 
and then with a slight excess of NH 4 OH. The precipitate 
is then filtered off, washed and dried, ignited and weighed 
as A1 2 0 3 . 

Calcium.— If the filtrate and washing from the iron 
and alumina precipitate is large, evaporate down to about 
150 c.c., add a little NH 4 OH, and then a slight excess of 
ammonium oxalate, filter, ignite, and weigh the precipitate. 
From the result thus obtained, the percentage of calcium 
oxide, CaO, is calculated. 

Magnesium. —The filtrate and washing from the cal¬ 
cium oxalate precipitate is evaporated to dryness, ignite 
the residue, and treat it with a little strong HC1, add water, 
and filter if necessary. To the filtrate add NH 4 OH in 
moderate excess, and then an excess of a solution of 
hydrogen disodium phosphate. Allow the liquid to stand 
for a few hours, as the precipitate is a crystalline compound. 
Its formation is accelerated by vigorously shaking in a 


168 ANALYSIS OF FIRE-BRICKS AND FIRE-CLAY. 

stoppered bottle; filter off, wash precipitate with dilute 
ammonium hydrate solution, then ignite it, and weigh the 
Mg as Mg 2 P 2 0 7 . 

Potassium and Sodium. —As sodium and potassium 
carbonates have been employed in “opening up” the 
silicate, it is obvious that the alkali metals cannot be 
estimated in a solution so obtained. 

A separate portion of the substance must accordingly 
be used for their determination. 

Weigh out 2 grams of the finely powdered substance 
into a platinum crucible. Well mix it with about six 
times its weight of pure calcium carbonate, and its own 
weight of pure ammonium chloride. The platinum crucible 
is placed in a clay crucible containing a little lime or 
calcined magnesia at the bottom and round the sides. The 
whole is now placed in a furnace, and maintained at a 
bright red heat. This heat is maintained for one hour. 
The crucible is now withdrawn, allowed to cool, then place 
the platinum crucible and contents in hot water in a covered 
platinum or porcelain crucible or dish, and boil for a time. 
The crucible is now withdrawn and rinsed, and the liquid 
is filtered, the residue being well washed. The solution 
now contains the alkali metals in the form of chlorides, 
is freed from any lime salts which have dissolved by the 
addition of ammonia, ammonium carbonate, and ammonium 
oxalate. The precipitate is filtered off, evaporate filtrate 
to dryness with a few drops of HC 1 in a weighed platinum 
dish ; finally raise to redness. The residue is now gently 
ignited and weighed until the weight is constant. The 
weight thus obtained gives the combined weight of potas¬ 
sium and sodium chlorides. 

In order to estimate the relative proportions of the 
potassium and sodium chlorides, the residue is dissolved in 
a very small quantity of water, and the potassium precipi¬ 
tated by the addition of an excess of platinic chloride 
solution. Adding a few drops of hydrochloric acid the 


SrECIFIC GRAVITY, VOLUME, WEIGHT, AND POROSITY. 169 

mixture is now evaporated on a steam bath until it becomes 
semi-solid. 

Alcohol is now poured on the mass, and the liquid 
gently shaken round in the dish, so as to well mix the 
contents ; the precipitate is allowed to settle completely, 
and the liquid poured off through a tared filter paper. 
The precipitate in the crucible is washed with alcohol two 
or three times; the undissolved precipitate is now transferred 
to the filter by means of a small wash-bottle filled with 
alcohol. The precipitate is washed with alcohol until the 
washings are no longer coloured. The filter is then with¬ 
drawn from the funnel, folded, and placed between a pair 
of watch glasses, and dried in the oven at 100 degrees 
Cent., and weighed as 2KClPtCl 4 . On deducting the 
weight of potassium chloride so obtained from the weight 
due to the mixed chlorides, the proportion of sodium 
chloride is found. 

Specific Gravity, Volume Weight, and Porosity.— 

In the Society of Chemical Industry Journal , 15 th February 
1906, p. 102, Dr E. A. Wagstaffe, in a paper entitled 
“Chemical and Physical Valuations of some Clays and 
Shales for Brickmaking, chiefly from East Cheshire,” 
gives the following :— 

The weight of the briquette having been ascertained, 
the briquette was soaked in water for twenty-four hours, 
taken out, and the surface water removed with a dry cloth. 
The increase in weight gives the amount of water absorbed 
by the briquette, *>., the amount that fills the pore spaces. 
The volume of the briquette is determined by displacement 
of water. The volume may also be determined by measure¬ 
ment, provided the briquette has not suffered any unequal 
contraction, whereby the shape has become distorted. 
Then if the weight of the briquette in grams is w, and 
the increase in weight due to absorption of water is t , 
and the volume in c.c. displaced when water saturated 
is v , 


70 


ANALYSIS OF FIRE-BRICKS AND FIRE-CLAY. 


the specific gravity = 




the volume weight = —, 
v 


porosity = 


too x / 

w 


Analysis of Weldon Mud. —This material for gas 
purification was brought before the gas world by J. J. 
Hood and A. Gordon Salamon in a paper entitled “ The 
Application of Weldon Mud to Gas Purification,” read 
before the Institute of Gas Engineers, and published in the 
Transactions of that Institute for 1893. 

In this paper the authors say: The material is that 
which is known to the alkali industry as Weldon mud, 
a compound consisting essentially of hydrate oxide of 
manganese. 

It is affirmed, as a great recommendation of Weldon 
mud, that the spent material can be regenerated upon an 
economical basis for further use in gas purification. Theo¬ 
retically there should in this process be no loss of the 
manganese constituents of the Weldon mud. 

It is worked through a cycle, viz., manufactured, next 
employed in the removal of sulphur, and when sufficiently 
saturated, submitted to regeneration. 

During this latter process it parts with all its sulphur, 
and as a result of the regeneration it is restored to its 
original condition, and is ready for further use by the gas 
engineer. Its regeneration being economical, the authors 
assert that it will be found, when worked under the best 
conditions, to compare favourably in price with other gas- 
purifying materials. 

The Weldon mud was found to be a sharp and powerful 
absorbent of sulphuretted hydrogen, and that the sulphide 
of manganese resulting from such absorption could be 
revivified in situ by the admission of a regulated sufficiency 
of air. 




WELDON MUD. 


171 

It was found that Weldon mud required about 1.0 per 
cent, of atmospheric air for revivification in situ , and that 
when this quantity was admitted it remained active for 
some considerable period. If the Weldon mud be in a 
position where condensation is a matter of certainty, it will, 
by virtue of its physical structure, absorb the water thus 
condensed, and when saturated may have to be taken out 
in a wet and sloppy condition. 

If the mud thus removed be spread in thin layers, and 
freely exposed to the action of the air it will dry, and can 
be broken, &c., and will then be active for further sul¬ 
phuretted hydrogen absorption. 

The analysis of a sample of Weldon mud works out as 
follows:— 


Water 

- 

40.60 per cent. 

Manganese dioxide - 

- 

29.80 

>> 

Calcium carbonate 

- 

10.60 


Calcium chloride 

- 

3.01 

> > 

Calcium sulphate 

- 

2.64 

>> 

Calcium hydrate 

- 

3.01 


Loss on ignition 

- 

9.80 

>> 

Fe 2 0 3 , MnCL, &c. 

- 

o -54 

>> 


100.00 


Great care must be given in taking a representative 
sample of Weldon mud ; it should fill the bottle completely, 
be well corked and sealed, if not, owing to various changes 
in temperature, small globules of water will separate out on 
to the sides of the bottle. It is only usual to analyse the 
sample for the amount of water, and for the manganese 
dioxide. The samples usually contain from 40 to 46 per 
cent, of water, and from 25 to 32 per cent, of manganese 
dioxide. The moisture is estimated in the usual manner 
by drying in a water bath at 212 degrees Fahr. until a con¬ 
stant weight is obtained, twenty-four hours being generally 
sufficient for this purpose. 

For the estimation of the manganese dioxide the avail¬ 
able oxygen is the oxygen which can be made use of for 



172 ANALYSIS OF FIRE-BRICKS AND FIRE-CLAY. 


oxidising purposes, when the ore is decomposed by an acid. 
The method used is where the evolved oxygen is used in 
oxidising a ferrous salt; therefore, if a known quantity of 
Weldon mud be dissolved in sulphuric acid, in the presence 
of a known quantity of ferrous salt in excess, and if the 
amount of the ferrous salt which remains unoxidised be 
then determined by means of a decinormal permanganate of 
potash solution, the quantity of iron oxidised, and therefore 
the amount of manganese dioxide, can be calculated. 

N 

The — permanganate solution is made as usual, and 

the iron solution is prepared as follows :—ioo grams of 
pure, dry, clean crystallised ferrous sulphate are dissolved 
in distilled water, to which is added ioo c.c. of pure con¬ 
centrated sulphuric acid, and the total made up to 1,000 c.c. 
at 60 degrees Fahr. with distilled water. The exact strength 
of this solution is ascertained by titrating 20 c.c. with the 
decinormal permanganate. If the ferrous sulphate is pure 
and unoxidised it will require 72 c.c. of the decinormal per¬ 
manganate to oxidise the 20 c.c. The exact amount of 
permanganate required is noted ; this must be carried out 
for every test, because the solution will oxidise even when 
kept in very closely stoppered bottles. 

0.5 gram of Weldon mud is now weighed out, washed 
into a small beaker, and 20 c.c. of the iron solution added. 
The whole is now boiled until all the Weldon mud is dis¬ 
solved, being aided if necessary by breaking the lumps with 
a glass rod (flattened at one end) against the bottom of the 
beaker. When the mud is completely dissolved the solu¬ 
tion is titrated with the decinormal permanganate, and the 
volume of the latter required for oxidation noted. 

Example — 

20 c.c. of ferrous sulphate solution required 71.6 c.c. — per- 

10 

manganate solution for oxidation. 

0.5 gram Weldon mud dissolved in 20 c.c. of ferrous 


WELDON MUD, 


173 






































































































74 ANALYSIS OF FIRE-BRICKS AND FIRE-CLAY. 


sulphate solution required 43.10 c.c. of decinormal permanganate 
solution. 

N 

Therefore 71.6 - 43.1 = 28.50 c.c. — permanganate. 

10 

Therefore, as 1 c.c. of decinormal permanganate is equivalent 
to 0.00435 gram of manganese dioxide, then the 0.50 gram 
Weldon contains 38.5x0.00435x200 = 24.795 per cent, of 
manganese dioxide. 

Sometimes there is a slight difference in the analyses 
done by various people ; if the analyses are calculated on 
the dry basis it will be found that they generally agree. It 
is usual to do at least two samples of Weldon mud, and 
they must agree to 0.20 per cent., if not, a third must be 
done. 

If the affinity of a sample of Weldon mud for sul¬ 
phuretted hydrogen is required, it is carried out in a similar 
manner as that described under oxide of iron. 

The chart on previous page shows the percentage of 
sulphur which is usually absorbed by Weldon mud with¬ 
out the addition of oxygen (in the form of air) for revivi¬ 
fication in situ , the revivification being carried out separately 
for each fouling. 

Analysis of Spent Oxide. —This method is based on 
the fact that free sulphur is dissolved by bisulphide of 
carbon. This bisulphide is evaporated off, and the sulphur 
is left behind in the solid form, in which state it may be 
weighed. 

It is necessary to remember that carbon bisulphide will 
only dissolve the free sulphur, and it is advisable to spread 
some of the sample out to the air for complete revivification 
before proceeding to extract the sulphur. 

Carbon bisulphide only imperfectly dissolves sulphur in 
the presence of water, so that the sample must be dried 
at 212 degrees Fahr. first. The apparatus employed is 
shown in Fig. 40, and was designed by Mr A. Stephenson 
of the Gas Purification Company. 


SPENT OXIDE. 


175 


50 grains of spent oxide are weighed out on a tared 
watch glass, and dried at 212 degrees Fahr. for moisture. 
This is weighed until the weight is constant and gives the 
moisture in the sample. Another 50 grains of the material 
which was placed out for complete revivification is dried in 
the oven. This does not give the true moisture, as it may 
have dried whilst laying out. This sample is carefully placed 
in tube A on the top of a layer of cotton wool. After 
putting in the dried oxide more cotton wool is put in on top. 
Bisulphide of carbon is blown from bottle B into test-tube 
A on top of the spent oxide. The CS 2 gradually percolates 



Fig. 40.—Apparatus for Estimation of Sulphur in Spent Oxide or Weldon Mud. 


through the material, dissolving the sulphur in its course, 
finding its way into flask C (which has been previously 
dried and weighed). The flask C is placed in a copper 
water bath which is kept boiling by the Bunsen burner. 
The CS 2 is driven off and is condensed in its passage 
through the condenser, and is recovered in the liquid state 
in flask D. The recovered CS 2 can be used over and over 
again. The sulphur remains behind in flask C. The 
oxide is well washed with CS 2 until free from sulphur, 
and when the sulphur is solid in the flask C it is discon¬ 
nected and put into a water bath for three or four hours 























176 ANALYSIS OF FIRE-BRICKS AND FIRE-CLAY. 


to eliminate the last traces of CS 2 . 


The increase in weight x 2 


Place in desiccator and 
percentage 


weigh when cold 
of sulphur on wet basis. 

It should be remembered that CS 2 is very inflammable, 
and in the gaseous state, when mixed with certain per¬ 
centage of air, highly explosive. The bisulphide should 
always be covered with water. 

Another method for extraction 
of sulphur is by the ordinary 
Soxhlet apparatus. A most use¬ 
ful adaptation of this is shown in 
Fig. 41. The only other com¬ 
pound required to be estimated in 
spent oxide is the total ferro- 
cyanide. This is not usually 
extracted in the oxide in this 
country, but sometimes it is. The 
method is as follows :— 

A weighed portion, say 10 
grams, of the spent oxide is well 
powdered in a mortar, and is 
digested with a strong solution 
of caustic soda boiled, and the 
solution filtered off. The total 
ferrocyanide can be estimated in 
many manners—(1) by precipi¬ 
tating as Prussian blue as given 
in cyanogen analysis; (2) by 

zinc sulphate ; or by the follow¬ 
ing method :—The caustic soda solution is evaporated to 
dryness, with sulphuric acid in excess. The residue is 
dissolved in dilute sulphuric acid, filtered, and the iron in 



Fig. 41. — Soxhlet Apparatus 
for the Estimation of Sul¬ 
phur in Spent Oxide or 
Weldon Mud. 


the filtrate reduced by zinc, 
dichromate. 

From the amount of iron 
Prussian blue can be calculated. 


Titrate with ^ potassium 


so found the amount of 




























CHAPTER XI. 


P HO TOME TRY AND GAS TES TING. 


The art of photometry is the art by which the ratio 
between the amount of light emitted by two sources is 
ascertained. 

The first law is “ Kepler’s Law of Inverse Squares,” 
which is that “ the quantity of light falling on a given 
surface varies inversely as the square of the distance from 
the source.” 

The second law is “ Lambert’s Cosine Law,” which, 
however, is only approximately true, and is that “ the in¬ 
tensity of illumination which is received obliquely, is pro¬ 
portional to the cosine of the angle which the luminous 
rays make with the normal to the illuminated surface.” 

The third law is the “ Generalised Photometrical Law ” 
I cos. 9 


which is that e 




where e is the light falling on a 


given surface, I the intensity of the source, 6 the angle 
of incidence of luminous ray, and d the distance of the 
source from the screen. 

Now with these three rules, which form the basis of 
all photometrical works, no further study of physics is 
absolutely necessary for the comprehensive study of 
photometry. 

In the early days of photometry the standard of light 
was the sperm candle of six to the pound, each burning 
120 grains per hour. Few candles burn at this exact rate, 
and in practical photometry a correction is made for the 

M 



178 PHOTOMETRY AND GAS TESTING. 

amount of sperm consumed, either more or less than this 
amount. 

Numerous other standards have been proposed during 
the last few years, and the official standard of light is 
now Mr Vernon Harcourt’s 10-candle pentane standard 

lamp. 

This 10-candle pentane 
lamp is one in which air is 
saturated with pentane va¬ 
pour, the air gas so formed 
descending by its gravity to 
a steatite ring burner. The 
flame is drawn into a definite 
form, and the top of it is 
hidden from view by a long 
brass tube, in which the air is 
warmed by the chimney, and 
so tends to rise. This creates 
a current, which, descending 
through another tube, supplies 
air to the centre of the 
steatite ring burner. No glass 
chimney is required, and no 
exterior means have to be 
employed to drive the pen¬ 
tane vapour through the 
burner. (Complete particulars 
are given in Appendix A.) 
The next standard of 

fig. 42.—Methven Screen. light substituted for the old 

sperm candle is the Methven 
screen, modified forms of which are used where officialism 
does not stipulate for the use of the Harcourt standard. 
The invention originally appeared about 1878, and is the 
invention of Mr John Methven of the Gas Light and Coke 
Co. In a communication to the meeting of the Gas Insti¬ 
tute in June 1882, Mr Methven described a modified form 














METHVEN SCREEN. 


1 79 


of this standard. This consisted of a standard Argand 
burner consuming coal-gas enriched by the vapour of 
pentane. A screen allowing only the light from a small 
portion of the flame to pass through was used. 

The flame of the standard Argand used was regulated 
to a height of 2 \ in., and the dimensions of the slot were 
altered from his original form to suit the shorter and 
more luminous flame. The dimensions given by Mr 
Methven are in the above paper, being about 15 mm. high 
and about 8 mm. wide, and the light was to be taken from 
a portion 24 mm. above the burner. Heisch & Hartley 
issued in 1883 a very favourable report on the Methven 



Fig. 43.—Graduated Bar with Carriage. 


screen as a method of obtaining a convenient standard light. 
The height of the flame should not deviate from the normal. 

As will be seen from the illustration, the Methven 
screen has two bars for adjusting the height of the flame, 
and two slots. The lower bar and smaller slot are for use 
on carburetted coal-gas, and the higher bar and larger slot 
for use on uncarburetted coal-gas. 

The carburettor, which must be perfectly air-tight, 
consists of a metal box with inlet and outlet pipes, both 
provided with taps ; there is also a by-pass between the 
inlet and outlet pipes, likewise furnished with a tap, so that 
the gas can be supplied to the burner either carburetted 
or uncarburetted. 













' l80 PHOTOMETRY AND GAS TESTING. 

Photometrical Testing.— The photometrical room 
should be of convenient dimensions. It should be well 
ventilated and free from draughts, not subject to vibra¬ 
tions, and should be maintained as near as possible to a 
temperature of 60 degrees Fahr. as circumstances will 
permit. The walls of the room should be coloured 
dull black, but need not necessarily be black all over, but 
should preferably be of a dull colour. 

The apparatus consists generally of what is known 

as the Letheby- 
Bunsen Photometer 
(except where the 
Referee’s apparatus 
is used, see Ap¬ 
pendix A.). 

The complete 
apparatus consists 
of a candle balance 
or some other stan¬ 
dard, Bunsen disc 
box or Simmance- 
Abady “Flicker” at¬ 
tachment, Argand 
burner for testing 
gas under consider¬ 
ation, meter, gover¬ 
nor, &c., as shown in 
figure. 

When using the candle balance, the Gas Referees 
assume that the illuminating power of a candle varies 
strictly as the rate of consumption of the sperm for varia¬ 
tions of not more than 6 grains per hour above or below 
the normal rate, i.e. y if the rate of consumption of a candle 
exceeds 126 grains, or falls short of 114 grains per 
hour, any test made under these circumstances must be 
discarded. 



Fig. 44.—Bunsen Reversible Disc Box 
with Mirrors. 











































































LETHEBY-BUNSEN PHOTOMETER, 


181 




Fit,. 45. 60-iNfcH Lethery-Bunsen Photometer. 













































































82 


PHOTOMETRY AND GAS TESTING. 


The Candle Balance.—The method of working the 
candle balance is as follows :—A candle is cut in half and 
fixed in the clips provided ; this is best done by laying the 
candle on a clean level surface, and rolling it under the 
edge of a sharp knife. Cut away half an inch of sperm 
from the top of the lower half, and the same from the 
bottom half of the other, reduce the wicks to half an inch 
in length. The candles are now ready for burning, and 



Fig. 46.—Candle Balance. 


should burn at least fifteen minutes before testing. The 
wicks of the candles should bend away from each 
other. 

Put weights in candle pan of balance until candles are 
slightly heavier than counterbalance. As the burning of 
candles makes them lighter than the counterbalance, the 
pointer will move over indicator, and as it passes the zero 
mark on indicator start the test clock. Gently lower beam 
until both pans are at rest, and then add the 40 grains 
weight to the candle end, and gently lift beam so that 
balance is once more in action. 



CANDLE STANDARD. 


183 

Make readings on bar by adjusting disc box until the 
grease spot is equally indistinct on either side, and note 
down reading. Ten observations are made, one at the 
beginning of each minute. 

Example — 


1st minute 

- 

8.2 

2nd 

>> 

- 

8-3 

3 rd 

>» 

- 

8.4 

4th 


- 

8-5 

5th 


- 

8.0 

6th 

,, 


8.2 

7th 

>> 


8.4 

8th 

>> 

- 

8.3 

9th 

>> 

- 

8.2 

10th 



8.2 

82.7 

e disc 

is reversed 

at end of 5th minute to balance 


possible inequality in the two sides. 

Divide 82.7 by 10 = 8.27. 

After the tenth reading watch candles very closely, 
and directly the pointer begins to move, be prepared 
to stop the clock directly the pointer passes zero mark 
on indicator (showing that 40 grains have been con¬ 
sumed), stop clock and note time, say 9 minutes 45 
seconds. 

In this test the gas under observation is always 
burnt at 5 cub. ft. per hour, so that it only requires an 
occasional glance to ascertain that this rate is constant, 
which is an easy matter; but say the consumption is 
a little fast, viz., 5.1 cub. ft., we now have the following 
data :— 


9 45" 

8.27 

5.10 


1. The time taken to burn 40 grains 

2. Average reading of candle power 

3. Gas consumption 


8 4 


PHOTOMETRY AND GAS TESTING. 


The working of the result is :— 
8.27 

2 


16.54 

5 

5.1)8270(16.21 candles at 5 cub. ft. per hour. 
5i 


•3i7 

.306 


. 110 
.102 


.80 

Corrected average for gas= 16.21 
Time due to 40 grains consumption in seconds = 600 


Then— 


9726.00 

Time actually occupied 9' 45" = 585 seconds. 
585)9726.00(16.62 

585 


.3876 

•35io 


.3660 

• 35 IQ 


.150° 

16.62 -i- Tabular number, correction for temperature and pres¬ 
sure = 1.036. 

1036)16.62(16.04 equals corrected candle power. 
10.36 


.6260 

.6216 


.4400 

Therefore the correct illuminating power of the gas tested is 
16.04 candles at the 5 cub. ft. per hour rate. 












FLICKER PHOTOMETER. 


85 


For using the Methven screen or Harcourt standard 
fitted to this type of photometer the method can either be 
on the 5 cub. ft. per hour rate, or on the 16-candle basis. 

The 5 cub. ft. per hour rate .—The gas is burnt at the 
rate of 5 cub. ft. per hour, and readings are made on bar 
by adjusting disc box as before, and in the case of Methven 
screen (being a 2-candle standard) multiply readings by 
2 and correct for N.T.P. 

Sixteen-Candle Basis .—The disc box is set at the figure 
8, and the gas is regulated so that the grease spot is 
equally indistinct on either side, then the minute clock is 
started, and the rate of consumption taken. 


Example — 


then— 


Disc set at 8.0, rate of consumption 5.1 ; 

5.1)8.000(15.68 candles. 

5i 


and 15.684-1,012 (Tab. No.)= 15.49 corrected candle power. 

The complete method of gas testing as required by the 
Gas Referees is given in the Appendix A. 

The “Flicker” Photometer —Patent No. 4,693, 28th 
February 1903, by J. F. Simmance and J. Abady. 

In the specification it is set out that careful investiga¬ 
tion and experiments have proved that the physiological 
causes of the little known optical phenomena described 
herein have been hitherto misunderstood, and attempts to 
utilise them in photometry have in consequence been 
abortive. The blurring, flickering, or throbbing effect pro¬ 
duced upon the eye by the rapid alternation of rays from 
the light under test and a comparison light (each of a 
distinct tint and intensity) is caused by the anxiety of the 
nerves controlling the dilation and contraction of the pupil 
to fulfil their office, whilst the effort to do so is frustrated 
by the rapid changing. The relief afforded by the arrival 


186 PHOTOMETRY AND GAS TESTING. 

at equal intensities of the two lights signals unmistakably 
the point when such equality has been reached. 

To arrive at the comparative intensities of light it is 
usual to allow rays from one of unknown power and also 
one of known power to fall upon a prepared surface, and 
there to compare the illuminating effect, which, however, 
presents difficulties when the lights are of different tints. 
They propose, therefore, to interpose between the lights 
and the illuminated surface an arrangement which will, at 
will, cut off the rays of either light, but not both entirely, 
or else portions of each light can be obscured, leaving only 
visible on the illuminating service the part where the two 
rays come in contact. Thus a suitably slotted plate will 
allow both beams to fall side by side if the receiving 
surface is at the proper distance from the slot, while by 
moving the slotted plate either light can be shut off and 
the receiving surface only receives the ray from one. Thus 
with two lights, one red and one blue, the slotted plate 
placed at one extremity of its slide will let fall upon the re¬ 
ceiving surface a beam of, say, red. Moving the plate slowly 
across the field the blue ray enters and the two colours are 
side by side. A further movement in the same direction 
and the field is entirely blue. It is found that the eye is 
only sensitive to these changes of colour when the plate is 
moved comparatively slowly; when moved rapidly to and 
fro only a blurred image with a throbbing effect is ex¬ 
hibited. This only results when the lights are of unequal 
intensity. When equally intense the two colours blend 
into a homogeneous tint and no throbbing is shown. Thus 
relative intensities of compared lights can be estimated 
either by simply comparing the two lights side by side on 
a receiving surface—and this only yields accurate results 
when the lights are nearly, or of, the same colour, and does 
not in any way eliminate the personal “error”—or by 
causing the cutting-off plate to oscillate at a suitable speed, 
which enables the relative intensities of lights of widely 
differing colours to be estimated with certainty. A finger 




SIGHTING WHEELS. 


187 


of wood or metal (moved in front of the receiving screen 
so as to cut off each light alternately) acts in the same 
way as the slotted plate, or a wheel with suitable vanes 
revolved has the same effect. In these instances the 
rays of light pass direct from their source to the eye, or 
rather to the intervening translucent screen or receiving 
surface. 



Fig. 47. —Sighting Wheels for Simmance-Abady’s “Flicker” Photometer. 


The above sketch shows a series of spare sighting 
wheels for Simmance - Abady’s “ Flicker ” photometer. 
When the lights are unequal the disc (one of the wheels 
above) shows a rapid throbbing, but when the intensities 
are equalised, the disc becomes a clear, steady blend of the 
two colours. It was found that with lights of the same 
colour the arrangement affords means for a very delicate 
test, and until the two lights are equal in intensity the 
throbbing or flicker effect is very marked, which ceases on 
equality being obtained. 




1 88 PHOTOMETRY AND GAS TESTING. 

Fig. 48 shows the flicker photometer head adapted 
to an ordinary photometrical bar —A, sighting tube; B, 
box containing wheel (as shown in previous figure), divided 
quadrant; and it also contains a spring motor, stopping, 
starting, and speed regulating lever, sighting lenses or 



Fig. 48.—Simmance-Abady “Flicker” Photometer Head. 


angle finder. The method of use is simple. The white 
screen is allowed to revolve (the speed is adjustable). A 
portion of the wheel is viewed as a disc (focussed by the 
telescope to suit observer). When the lights are unequal, 
a “ flickering ” effect is observed. When equality has been 
obtained, the flickering ceases, and a clear, apparently 

























STREET PHOTOMETRY. 189 

motionless disc is observed. Any difference in colour 
between the contrasted lights is immaterial. 

Street Photometry.—The photometer consists of a 
triple chamber of mahogany containing (1) a Simmance & 
Abady “ Flicker ” head angle form, (2) a brass screen with 
variable opening, and (3) a pentane burner with automatic 
carburettor. The flicker head has already been de¬ 
scribed, and by its means the angle of light can be found. 
The pentane flame is fed with pentane air gas by gravity 
from the carburettor, and burns to a fixed height quite 
steadily and undisturbed by outside conditions. The brass 
screen divides the flame from the flicker head, and its 
two shutters, meeting at a line central with centre of disc, 
are capable of being opened and closed by means of a 
handle with divided drum outside the central portion of 
box. The adjustment can be made and read to 2V milli¬ 
metre, and alters the light falling upon the disc by as fine 
an adjustment as of a foot candle, the maximum light 
being nine foot candles. 

The divisions on the divided drum of handle are I in. 
per mm., running on a spiral, and can easily be read by 
light reflected from the pentane lamp by a mirror provided 
and set at a suitable angle. The photometer head itself is 
provided with shield from extraneous light. 

To make a test with the above photometer put down 
view finders and shutters of flicker, adjust pentane flame 
to proper height (by coincidence of tip of flame with the 
height mark), start flicker, having wound the clock. 
Observe the flicker, and turn the handle with divided 
drum. This will vary the orifice in front of the pentane 
flame, and when the flicker disappears take a note of the 
figure on drum coincident with the arrow indicator. Make 
as many readings at each angle as the type of lamp necessi¬ 
tates ; with a steady light one reading suffices, a flickering 
arc requires, perhaps, a dozen ; in each case make a note of 
the figure upon the divided drum. Measure the distance 


PHOTOMETRY AND GAS TESTING. 


190 

from source of light to centre of flicker disc ; if, as is 
generally the case, this is impracticable, then note firstly 
the angle (not the halved angle), and either the length of 
perpendicular or base line, as explained. This gives the 
distance from the light to the disc. You thus have the 
following particulars :— 

1. (a.) Distance of light from flicker disc in feet. 

(1 b .) Condition which created a balance, i.e., either 
extent of opening of shutter, or voltage of electric lamp or 
both. 

The remainder of the test is made in the laboratory or 
photometrical room afterwards, as follows :— 

2. (a.) Place photometer on the saddle provided, which 
travels on base board provided. 

(p.) Reconstitute the conditions by opening shutter as 
it was at test, or regulating lamp to same voltage, or both. 

(c.) Light the Simmance 1-candle standard supplied, 
and place it at a suitable distance from, and in line with, 
centre of flicker disc. 

('/.) Turn this latter to horizontal, and move photometer 
(on its saddle) until equality is obtained. 

Measure distance from 1-candle standard to flicker 
disc. 

You thus obtain, in lieu of 1 (£), the distance in feet at 
which a candle must be held to balance the light at the 
particular angle tested. Q.E.F. 







ILLUMINATING EFFECT PHOTOMETER. 


IQI 


SlMMANCE AND AbADY’S PATENT ILLUMINATING EFFECT 

Photometer. 

Table giving multipliers or factors for different angles, which 
factor, when multiplied by the square of the base line, gives 
the square of the distance from the light under test to the 
disc. 


Angle. 

Factor. 

Angle. 

Factor. 

Angle. 

Factor. 

Angle. 

Factor. 

Degrees. 

IO 

1.026 

Degrees. 

40 

I.704 

Degrees. 

52 

2.638 

Degrees. 

64 

5.204 

15 

I.070 

40.5 

I.729 

52.5 

2.698 

64.5 

5-395 

20 

1.130 

41 

1-755 

53 

2.76l 

65 

5-599 

25 

I.205 

41.5 

1.782 

53-5 

2.826 

65.5 

5.815 

30 

1-333 

42 

1.811 

54 

2.894 

66 

6.044 

30-5 

1-347 

42.5 

1.84 

54-5 

2.965 

66.5 

6.289 

3 i 

1.36 

43 

1.87 

55 

3.039 

67 

6.55 

3 i -5 

1-375 

43-5 

1.901 

55-5 

3 -i 17 

67.5 

6.828 

32 

i -39 

44 

1.933 

56 

3.198 

68 

7.126 

32.5 

1.406 

44-5 

1.966 

56.5 

3-283 

68.5 

7445 

33 

1.422 

45 

2.0 

57 

3 o 7 i 

69 

7.786 

33-5 

1.438 

45-5 

2.035 

57-5 

3464 

69.5 

8.153 

34 

1-455 

46 

2.072 | 

58 

3-561 

70 

8.548 

34-5 

1.472 

46.5 

2.111 

58.5 

3-663 

70.5 

8-974 

35 

1.49 

47 

2.15 

59 

3-77 

7 1 

9-434 

35-5 

1.508 

47-5 

2.19 

59-5 

3.883 

71.5 

9-932 

36 

1.527 

48 

2.233 

60 

4.0 

72 

10.472 

- 36.5 

1-547 

48.5 

2.277 

60.5 

4.124 

72.5 

11.059 

37 

1.568 

49 

2.323 

61 

4.254 

73 

11.698 

37.5 

1.589 

49-5 

2.37 

61.5 

4-389 

73-5 

12.397 

38 

1.610 

50 

2.42 

62 

4-537 

74 

13.164 

38.5 

1.633 

50.5 

2.47 

62.5 

4.69 

74-5 

14.002 

39 

1.656 

5 i 

2.525 

63 

4.849 

75 

14,928 

39-5 

1.680 

51-5 

2.581 

63-5 

5.023 































192 


PHOTOMETRY AND GAS TESTING. 


The following diagrams will make this clear :— 

a is the source of light. 

ac is the length of column. 

cd is the ground line. 

bc is height of photometer centre ground. 

e is point where reading of I.P. was taken. 

bae is an angle of, say, 60 degrees. 

bea is therefore an angle of 30 degrees. 

aed, representing the light ray, is the “ light at an angle of 
30 degrees ” (fae). 



Now you will have obtained the following data for each 
angle:— 

The distance ae in feet—let this = #. 

The distance in feet at which a candle is held to balance the 
light of a at e —let this = b. 

Then— 

The illuminating power (I.P.) of a in the direction aed 



The illuminating effect at E is either 

I P 

any further calculation, or else either 
yield, of course, the same figure. 


simply b , without 
or ^ ; both these 









MEAN SPHERICAL INTENSITY. 


193 


The following Tables give factors for calculating spheri¬ 
cal and hemispherical intensities, and are from a paper 
read by Jacques Abady entitled “ Light Measurements ” :— 


Mean. Spherical Intensity (reading every io°). 



N 




























194 


PHOTOMETRY AND GAS TESTING. 


Mean Spherical Intensity (reading every 15 0 ). 


Longitudes. 

Readings, Candle Power. 

Factor 

Mean 

Reading 

X Factor. 

0° 

90° 

180 0 

270° 

Mean. 

for Area. 

90 deg. N 

75 „ 

60 „ 

45 » 

30 )> 

*5 M 
Horizontal 

15 deg. 

30 „ 

45 „ 

60 „ 

75 „ 

90 „ S 






0.006 

O.032 

O.065 

O.09 

0.11 2 
0.125 
0.14 
0.125 

0.112 
O.09 
O.065 
! 0.032 
0.006 




Mean Spherical Intensity = 



Mean Spherical Intensity (reading every 22J 0 ). 







































MEAN SPHERICAL INTENSITY. 


195 


Mean Spherical Intensity (reading every 30°). 


Longitudes. 

Readings, Candle Power. 

Factor 

Mean 

Reading 

X Factor. 

0° 

90° 

180 0 

270° 

Mean. 

for Area. 

90 deg. N 

60 „ 

30 „ 
Horizontal 
30 „ 

60 „ 

90 „ S 






0.017 

0.13 

0.223 

0.26 

0.223 

0.13 

0.017 



Mean Spherical Intensity = 


Mean Hemispherical Intensity (reading every io°). 


Longitudes. 

Readings, Candle Power. 

Factor 
for Area. 

Mean 

Reading 

X Factor. 

o° 

90° 

180 0 

270° 

Mean. 

Horizontal 






O.085 


10 

deg. 






0.168 


20 







O.166 


30 

» 






0.15 


40 







O.I38 


50 







O.II2 


60 







O.09 


1 70 

j) 






O.06 


80 

)> 






0.028 

- 

90 

» s 






1 O.OO3 




Mean Hemispherical Intensity = 












































196 


PHOTOMETRY AND GAS TESTING. 


Mean Hemispherical Intensity (reading every 15 0 ). 


Longitudes.' 

Readings, Candle Power. 

Factor 

Mean 

Reading 

X Factor. 

o° 

9 °° 

180 0 

270° 

Mean. 

for Area. 

Horizontal 
15 deg. 

30 » 

45 „ 

60 „ 

75 „ 

90 „ S 






O.I4 

O.25 

0.224 

0.18 

O.I3 

O.064 

O.OI2 




Mean Hemispherical Intensity = 



Mean Hemispherical Intensity (reading every 22J 0 ). 


Longitudes. 

Readings, Candle Power. 

Factor 

Mean 

Reading 

X Factor. 

o° 

90° 

180 0 

270° 

Mean. 

for Area. 

Horizontal 
22^ deg. 

45 „ 

67 i » 

90 „ S 





■ 

cu9 

0.36 

0.28 

0.15 

0.02 




Mean Hemispherical Intensity = 













































HEATING VALUE OF GAS. 


197 


The heating value of gas has been brought more to the 
fore of late years, owing to the large amount of gas that is 
used for heating purposes, such as cooking, also that now 
the incandescent mantle is uniformly used, and that the 
light obtained from these is due to the heat derived from 
the gas on combustion. It is important for the gas engineer 
to be able to ascertain the heating or calorific power of his 
gas. The standard of heating value of a gas is taken as 
follows :— 

A calorie is the amount of heat required to raise 1 kilo¬ 
gramme (1 litre) of water 1 degree Cent. 

A British thermal unit (B.Th.U.) is the amount of heat 
required to raise 1 lb. of water 1 degree Fahr. 

Calories per cubic foot are the number of kilogrammes 
(litres) of water raised through 1 degree Cent, by the com¬ 
plete combustion of 1 cub. ft. of gas, corrected in volume 
to normal temperature and pressure. On the metric system 
it is expressed as calories per cubic metre, and is the 
number of kilogrammes (litres) of water raised through 
1 degree Cent by complete combustion of 1 cubic metre of 
gas. 

British thermal units (B.Th.U.) per cubic foot are the 
number of lbs. of water which can be raised through 1 degree 
Fahr. by the complete combustion of 1 cub. ft. of gas. This 
formula is generally used in this country, although, owing 
to the convenience attained by the coincidence of kilo¬ 
grammes and litres of water we use the metric water 
measure and the Centigrade thermometer, and calculate 
our results first in calories and then into B.Th.U. by multi¬ 
plying by the factor 3.97. 

To convert calories per cubic foot into B.Th.U. per cubic 
foot, multiply by 3.97 (3.968). 

To convert calories per cubic foot into calories per cubic 
metre, multiply by 35.316. 

To convert B.Th.U. per cubic foot into calories per cubic 
metre, multiply by 8.9. 

There are three or four well-known instruments on the 


198 PHOTOMETRY AND GAS TESTING. 

market by which a calorific test can be made. These 
are:— 

(1.) The Simmance-Abady Patent Calorimeter for Gas. 



Fig. 50.—Simmance-Abady Gas Calorimeter, 


lil.'Miimi.M 







































































































































































































SIMMANCE-ABADY CALORIMETER. 


199 

(2.) The Junker Calorimeter, invented by Herr Junker 
of Dressau. * 


a 


a 



Fig. 51.—Simmance-Abady Calorimeter—Sectional Elevation. 


(3.) The Boys Calorimeter, devised by Professor C. V. 
Boys, F.R.S., which is now the official instrument, and is 
described in the “Gas Referees’ Notifications.” 
































































200 


PHOTOMETRY AND GAS TESTING. 


i. The Sinnnance-Abady Patent Calorimeter for Gas. 
—The description of the apparatus is as follows, and can 
easily be seen by the accompanying illustrations:— 

A cylindrical vertical form is adopted, and the water 
enters at A and passes through the fine adjustment cock 
B. On its entry it fills to a certain height the tube C; the 
height of the water is denoted by the Erdmann float. It 
will be found convenient to mark the height of the water 
in tube C. A small rubber band sprung round it is most 
convenient, and the water should be turned on till this 
level is reached, and during all tests, and each time the 
three thermometers are read the regularity of the water 
level should be verified. 

After rising in the water gauge the water flows through 
the thermometer chamber D, thus giving the inlet tempera¬ 
ture. From thence it fills a water jacket enveloping the 
whole body of the calorimeter, and which is in its turn 
covered with a sheet of non-conducting material and 
lagged closely with polished wood strips, and thus is pre¬ 
vented all loss by absorption or by radiation. 

From the outer jacket chamber it passes down E into the 
calorimeter at the bottom of the cylinder, and rises up in 
an annular double skin (as shown by arrows), one side of 
which is exposed to the products of combustion at their 
point of exit, taking out from them the last degrees of 
heat left, whilst the other is the wall of the jacket 
chamber. 

From this point the water flows into a second chamber, 
entering it, as in the case of the first chamber, at the 
bottom, being conveyed by tubes from the top of the first 
to the bottom of the second. Here it is in contact with 
the products of combustion at an earlier stage of cooling. 
A third chamber brings it nearer the source of heat, and at 
this point it envelops the flame itself. Being warmed by 
its previous progress, it does not cause the violent absorp¬ 
tion of heat from the flame which would occur were it 
absolutely cold, and thus the structure of the flame is pre- 


SIMMANCE-ABADY CALORIMETER. 


201 


served, and there is no sudden condensation (to water) of 
products. 

Finally the water mounts into the receptacle H, immedi¬ 
ately above the flame, and receives the full first heat. In 
this chamber is inserted the outlet thermometer J, and from 
thence the water passes through IC to the measuring cham¬ 
ber M, or when the apparatus is not in use to waste by L. 

The flame is situated in the centre, well up in the calorir 
meter (the burner is constructed on the Bunsen principle, 
i.e.y non-luminous), in a chimney consisting of walls of 
water in thin copper skins. The heated products strike 
straight up to the top water chamber, which is filled with 
the hottest water, and so practically no condensation takes 
place at this point. Spreading out under this top chamber 
G, they reach the top of the outer water wall F, and 
there are suddenly and violently cooled, and here the 
greatest deposit of condensed water is made. The pro¬ 
ducts find themselves over the duple passage between the 
first and second, and second and third annular water 
chamber, and being unsupported and constantly increasing 
in weight, drop rapidly down PP, lapping over the cold 
surface in a clinging film. By the time they reach the 
bottom they are at the atmospheric temperature, and flow 
out through Q into measuring chamber R. 

Thus we have admitted water at a given temperature, 
and warmed it to a certain extent by the combustion of a 
known quantity of gas, the heat of which gas has been 
entirely expended on the water (all exterior parts of the 
calorimeter being at the temperature of the ingoing water 
and absolutely no heat being lost), so that all the heat is 
carried off by the waterflow and registered. The products 
of combustion must be at the atmospheric temperature, 
and this is ascertained by the thermometer placed in the 
outlet, but not in the condensed water. 

The why and wherefore of making a deduction for 
the amount of water condensed need not be discussed 
here, sufficient to say that it is done. 


202 


PHOTOMETRY AND GAS TESTING. 


We will say that the combustion of T V of a cub. ft. 
of gas has caused the condensation of 1.8 cub. cm. of water. 
Now, the latent heat of steam is 538 calories, i.e., to evapo¬ 
rate 1 litre of water from boiling point to steam has 
absorbed as much heat as would have raised it 538 degrees 
Cent, without increasing its temperature. Therefore in 
reducing steam to 1 litre of water at 100 degrees, 538 
units would have been liberated, and in bringing this down 
to atmospheric temperature a further 85 units should be 
added. 

We have collected 1.8 c.c. or .0018 of a litre of con¬ 
densed water, which therefore represents eighteen hundreds 
of 623 units=i.i224 for of a cub. ft., which (multiplied 
by 10 and deducted from the gross calories) gives us the 
net calories per cub. ft. 

This calculation can be saved, by multiplying the 
number of c.c. of water condensed by .6. 


Example — 

Temperature on inlet - 
„ outlet - 

„ outlet products 

Gas passed, cub. ft. 

Air temperature - 
Gas temperature - 
Water collected - 


• 1) 1-230 

i. 2 3° 

Difference in temperature = 11.2 


15.6° Cent. 

- 26.8° „ 

15-6° „ 

0.10 
15.6° Cent. 

- iS-6° „ 

1,230 c.c. or 1.230 litres. 


2460 

1230 

1230 


i 37-7 6 ° gross calories per cub. ft. 

Water condensed = 1.8 c.c. x 0.6 = 10.8 calories to be de¬ 
ducted from gross = 137.76 - 10.8= 126.96 net calories per cub. 
ft. = 126.96 x 3.97 = 503.63 B.Th.U (net) per cub. ft. at N.T.P. 




THE JUNKER CALORIMETER. 


203 


2. The Junker Calorimeter .—This calorimeter is on 
the same principle as the Simmance-Abady, the gas under 
experiment is burnt (in a Bunsen burner) in a combustion 
chamber formed by an annular copper vessel, the annular 
space being traversed by a number of copper tubes which 
connect the roof with the bottom chamber. 

The average calorific value of the various Gas Com¬ 
panies given in the Gas World for 2nd March 1907 are :— 



Illuminating Power 

in Sperm Candles. 

Calorific Power. 

Calories per Cubic Foot. 

By Metropolitan No. 2 
Argand. 

By Flat Flame 
Burner. 


Max. 

Min. 

Aver. 

Max. 

Min. 

Aver. 

Max. 

Min. 

Aver. 


I8.I 

15-99 

16.7 

12.8 

9-7 

u-9 

145.8 

127.5 

134.6 

TJ i 

I8.I 

16.00 

16.6 

13-3 

9.8 

12.0 

142.4 

125.1 

134-3 

§ d I 

17.8 

15.67 

16.7 

13-3 

9.8 

11.9 

142.7 

125.7 

134.6 

£ J 1 

18.4 

15.86 

16.6 

13-i 

9-7 

11.8 

153-5 

126.7 

134-1 

be 4) < 

18.8 

16.00 

16.7 

13.0 

10.5 

11.9 

155.6 

I24.3 

134.2 

J O 

17.9 

15.92 

16.7 

i3-5 

10.4 

12.1 

146.9 

1274 

135-2 

m U I 

I 

177 

15-74 

16.5 

12.9 

10.4 

u-9 

149.8 

123.4 

134.8 

O 

18.2 

14.83 

16.5 

i3-3 

9.6 

ii -7 

1494 

119-3 

133-3 


18.0 

16.0 

16.6 

13.0 

10.0 

11.7 

148.6 

121.6 

133.5 

0 / 

efi [ 

18.0 

14.8 

16.3 

12.8 

9.8 

11.2 

140.7 

128.2 

133-7 


17.7 

14.8 

16.0 

12.8 

9-3 

11.1 

138.9 

120.7 

132.4 

O 

Oh « 

17.3 

14.5 

15.8 

12.7 

9.4 

10.7 

1437 

127.3 

134.2 

26 

17.2 

14.6 

15.9 

13.0 

8.9 

10.9 

I50.9 

127.3 

133-7 

O <n ( 

17.3 

14.4 

15.8 

I 3- 1 

9.8 

10.9 

142.6 

127.8 

133-2 

^ O i 

17.6 

14.7 

l6.I 

13-4 

10.0 

n-3 

138.8 

129.3 

133-8 

■5 

17.2 

14.7 

15.9 

12.8 

9.4 

10.9 

136.7 

126.8 

132.9 

0 

18.3 

14.5 

l6.2 

13-i 

9-4 

11-4 

139-9 

125.1 

i35-o 

w \ 

17.8 

15.0 

16.2 

13.6 

9-5 

11-4 

142.2 

128.6 

136.1 

6 

16.5 

14.5 

154 

11.8 

8.6 

10.0 

134-3 

123-5 

129.0 

L> 

in 

l6.2 

14-3 

15*1 

10.3 

8-3 

9.4 

130.6 

121.8 

126.5 

a 

16.4 

14.0 

14.9 

11.1 

8.1 

9-3 

i4i-3 

124.1 

131-1 

O 

l6.2 

14.4 

15.2 

10.8 

8.5 

9.6 

133-3 

121.5 

128.7 

3 < 

15-7 

15.0 

15-3 

10.0 

9-3 

9-7 

135-3 

123.7 

129.5 

<D 

16.0 

14.4 

1 5* 1 

10.2 

8.2 

9.1 

132.6 

118.5 

127.7 

a 

16.4 

14.4 

15.0 

10.4 

8.2 

9.2 

13L6 

122.6 

126.9 

| 

16.4 

14.8 

15-5 

10.6 

9.2 

9-8 

129.8 

124.5 

127.6 

0 

. 157 

14.1 

1 5- 1 

9-9 

8.4 

9-3 

129.0 

119.5 

125.8 

















204 


PHOTOMETRY AND GAS TESTING. 


The products of combustion pass through these tubes 
in a downward direction, whilst a current of water 
ascends outside the tubes in an opposite direction. By 
this arrangement all the heat given out by the com¬ 
bustion of the flame is absorbed by the water, and the 
spent gases, together with condensed water, pass out 
through the side conduit at the temperature of the room. 

For the flat flame test, Bray’s No. 7 “ Economiser ” 
over Bray’s No. 4 “Regulator” as prescribed. The figures 
are taken from the weekly sheets, irrespective of the 
testing station at which they were obtained, and the average 
figures are the result of averaging the weekly averages of 
all the testing stations. The average is not a true one, 
but may be taken as fairly accurate. 

The prescribed illuminating power for the Gas Light 
and Coke Co. is sixteen candles, and for the other two 
companies fourteen candles. 

The calorific power of some of the principal gases 
expressed in B.Th.U. are:— 

Uncarburetted water-gas from - 270-296 

Carburetted water-gas of 21.9 candles - - - 624 

Coal-gas 16 candles (No. 2 London Argand) - - 580 

The calorific values of each of the combustible con¬ 
stituents of coal-gas, assuming that none of the steam 
resulting from the burning of the hydrogen is condensed 
to water, are :— 


Calories per cubic foot. 


Hydrogen - 

Methane 

Ethane 

Propane 

Butane 

Pentane 

Ethylene - 

Propylene - 

Butylene - 

Benzene (vaporised) 

Toluene 

Carbon monoxide 


242.1 
45°. 1 
645-3 

851.1 
1056.3 

404.3 

600.0 

821.0 

953-9 
1121.8 
85.8 


73-6 


CANDLES AND CALORIES. 


205 


With these figures and an analysis of the gas, it is pos¬ 
sible to obtain by calculation a close approximation to the 
calorific value of a sample of coal-gas. 

Prof. V. B. Lewes in a lecture entitled “ Candles and 
Calories,” read before the Institute of Gas Engineers in 
June 1903, gives the following as the constituents of coal- 
gas, and tabulates them according to their calorific value as 
follows 


Description of Gas. 

Calories per 

Cubic Foot. 

British Thermal Units 
per Cubic Foot. 

Gross. 

Net. 

Gross. 

Net. 

Benzene vapour - 

938.9 

902.5 

3,718 

3,574 

Ethylene - 

404.8 

381-3 

1,603 

1,510 

Methane - 

258.6 

232.O 

1,024 

919 

Carbon monoxide 

83-3 

83-3 

330 

330 

Hydrogen - 

82.0 

68.7 

325 

272 


Taking now an ordinary sample of 16-candle power 
coal-gas (old method No. I London Argand) as supplied 
to the City of London, and applying these values to its 
combustible constituents, we have :— 


Hydrogen 

Methane 

Ethylene 

Benzene 

Carbon monoxide - 


54 per cent, x 325 = 17,550 
34 „ x 1,024 = 34,816 

3 x 1,603= 4,809 

1 ,, x 3>7 i8 = 3,7 i8 

6 „ x 330= 1,980 


62,873 


or 628.73 B.Th.U. gross for a cubic foot; while if the 
calorific value be tested direct in the calorimeter, we 
obtain, as the value of the mean of ten determinations, 
by the Junker calorimeter, 157 calories per cub. ft, or 157 x 
3,968 = 623 B.Th.U. 

Another most interesting Table given by Prof. V. B. 












20 6 


PHOTOMETRY AND GAS TESTING. 


Lewes for the various calorific values of coal-gas and car- 
buretted water from 12 to 20 candles, is as under:— 


Calorific Value of Pure Coal-Gas. 


Candle Power. 

Calories. 

British Thermal Units. 

Gross. 

Net. 

Gross. 

Net. 

12 

I36.O 

120.6 

540 

480 

13 

141.0 

125.6 

560 

500 

14 

147.0 

131.2 

585 

522 

15 

153-2 

136.2 

609 

542 

16 

157.0 

141.2 

625 

562 

1 7 

162.5 

146.2 

647 

582 

18 

168.3 

151.2 

670 

603 

19 

173-3 

156.3 

690 

622 

20 

178.8 

161.3 

712 

642 


Calorific Value of Carburetted Water-Gas. 


Candle Power. 

Calories. 

British Thermal Units. 

Gross. 

Net. 

Gross. 

Net. 

12 

123.1 

H 3-5 

490 

452 

13 

128.1 

118.6 

510 

472 

14 

132.9 

122.8 

529 

489 

15 

137-4 

127.6 

547 

508 

l6 

I42.4 

132.4 

567 

527 

17 

147-5 

137-4 

587 

547 

18 

152.7 

142.4 

607 

567 

19 

157.5 

147-5 

627 

587 

20 

162.5 

152.5 

647 

607 


Flame Temperature. —This is a matter which has 
undoubtedly not received the attention (anyhow in this 
country) that it deserves. 

Undoubtedly, the actual flame temperature, or the 
temperature of a flame, is not denoted by its calorific 



















FLAME TEMPERATURE. 


207 


value at present. The calorimeter takes into account the 
total calorific value of a gas (the net value affecting the 
matter considerably), whereas the temperature of a flame 
depends chiefly on the amount of the substances to be 
heated to that temperature. 

In flame under consideration the only substances to 
be considered are nitrogen, oxygen, carbon dioxide, and 
water vapour. The nitrogen is the most important, being 
proportional to the oxygen required for combustion. The 
gas which requires more oxygen for combustion, and there¬ 
fore produces more water of condensation, will give a 
lower flame temperature in relation to its calorific power. 

The analysis of a gas has a great bearing on the flame 
temperature, for instance. Carbon monoxide has a much 
lower calorific power than ethylene, but gives a higher 
flame temperature, as more heat units are liberated in pro¬ 
portion to the air required for combustion, and a gas that 
contains a large proportion of hydrogen and a small per¬ 
centage of marsh gas would give more heat by a calori¬ 
meter, but would give a lower flame temperature because 
of the greater specific heat of water vapour as compared 
with that of carbon dioxide and nitrogen. 

M. Mahler, on the value of the Flame of Combustibles, 
says that the calorific power and the chemical composition 
are, in general, sufficient elements of comparison between 
natural combustibles. These data permit of the calcula¬ 
tion of the value of flames ; and the question may be 
asked of the practical utility of this. The value of the 
flame of combustible is the same thing as its temperature 
of combustion under constant pressure. It is measured by 
the thermometric degrees, through which the gaseous pro¬ 
ducts of the combustion are raised. Supposing them to be 
heated by all the gases due to the combustion and solely 
by it, and that the combustion is complete. Now it is 
clear that if the calorific value, the chemical composition, 
and the specific heat of the gas is known, the flame tem¬ 
perature can be calculated. 


208 


PHOTOMETRY AND GAS TESTING. 


Flame temperature is a theoretical absolute value 
which is not reached owing to the defective character of all 
heating apparatus, but nevertheless it is in many cases of 
the utmost value as a guide to the judgment. 

Mahler gave the following formula for calculating the 
calorific (g) under constant pressure of the unit weight of a 
fuel:— 

(i.) q — N(C///T 1 - O/T 0 ) 


in which C;// = the mean specific heat of one of the com¬ 
bustion gases between zero and T 0 on the 
absolute scale. 

N = the number of molecules in “ mol ” volumes 
of 22.32 litres (the “mol” is Ostwald’s 
term for the molecular weight in grams). 

T 0 = the initial temperature (from the absolute 
zero). 

T 2 = the final (or flame) temperature (from the 
absolute zero). % 

Specific heat increases with temperature, and the 
changes are so great at high temperature that they cannot 
be disregarded. Mallard and Le Chatelier apply the 
following equation to express the mean specific heat:— 

Cm = a + fS T, 


in which a and p are coefficients, having the following 
values for the different products of combustion :— 


a 

For the permanent gases (nitrogen - 1 

and carbonic oxide) - - 6.5 x 1,000 

- 1 

For superheated aqueous vapour 6.5 x 1,000 

- 1 

For carbonic acid - - - 6.9 x 1,000 


p 

- 2 

0.6 x 1,000 

- 2 

2.9 X 1,000 

- 2 

3.7 X 1,000 


Taking T 0 as 273 or o degrees Cent., and 0 as = the final 
temperature on the Centigrade scale, and T 1 therefore as 
= 0 + 273, then inserting the foregoing values in Equation 
(1) it becomes:— 


CALORIES OF THE “MOL” VOLUME. 


209 


2.) ? = n[- 


ad 


OOO 


+P 


(8 + 273)2" 2 73 2 


IOOO 


,2 


} 


The value of 0 can be found from this equation, if the 
number of molecules formed by the combustion and the 
calorific power stated in large calories are known. 

The Table shows the heat in calories of the “ mol ” 
volume of 22.32 litres under constant pressure for different 
gases:— 


Temperature. 

Nitrogen, Oxygen, 
Carbonic Oxide, 
Hydrogen. 

Superheated 
Aqueous Vapour. 

Carbonic Acid. 

Degrees Centigrade. 

Calories. 

Calories. 

Calories. 

O 

0.00 

0.00 

0.00 

IOO 

0.68 

O .83 

O .87 

200 

1-39 

1-73 

I .85 

3 °° 

2.10 

2.67 

2.87 

400 

2.82 

3^9 

3-99 

500 

3-56 

4.76 

5.17 

600 

4.31 

5.89 

6.44 

700 

5.07 

7.07 

7-77 

800 

5.85 

8.30 

9.16 

900 

6.63 

9.62 

10.66 

1,000 

7-43 

IO .98 

12.12 

1,100 

8.24 

12.40 

13.85 

1,200 

9.05 

I 3.87 

15-55 

1,300 

9.89 

1541 

17.33 

1,400 

10.73 

17.00 

19.18 

L 5 00 

11.59 

18.65 

21.11 

1,600 

12.46 

20.35 

23.09 

1,700 

1,800 

13.24 

22.13 

25.18 

M .23 

23.93 

27.31 

1,900 

15.14 

25.83 

29.55 

2,000 

16.05 

27.76 

31.83 

2,100 

16.98 

29.74 

34.18 

2,200 

17.92 

31.81 

36.64 

2,300 

18.87 

33-91 

39.14 

2,400 

19.84 

36 .IO 

41.75 

2,500 

20.81 

38.32 

44.40 

2,600 

21.80 

40.62 

47.16 

2,700 

22.80 

42.95 

49.96 

2,800 

23.82 

45-37 

52.87 

2,900 

24.84 

47.82 

55 . 8 i 

3,000 

25.88 

50-35 

58.86 


0 













210 PHOTOMETRY AND GAS TESTING. 

The approximate value of the flame temperature will 
usually be known, and trials are then made with the help 
of the table, taking the known number of molecules, until 
the temperatures in the table which give the calorific values; 
next, above, and below the ascertained value have been 
found. Then for the small interval of ioo degrees between 
the two temperatures no practical error will be introduced,, 
if the calorific value is taken as proportional to the tem¬ 
perature, and the exact value of the flame temperature thus 
ascertained. 

The method for using the table on p. 209 (and which 
facilitates the rapid solution of the equation) is as follows:— 

The combustion of hydrogen will serve as an example. 
There are four volumes of nitrogen introduced from the air 
with every “ mol ” volume of oxygen. The equation is :— 

H„ + ^ + 2N0 = 2N 2 + H .,0 (gaseous)+ 58.2 cal. 

2 

Thus the products of combustion of 1 molecule (2 grams) 
of hydrogen are 2 molecules of nitrogen and 1 molecule of 
aqueous vapour, and <7=58.2 calories. Assuming the 
probable temperature of combustion to be between 1,800 
and 2,000 degrees Cent., the calorific value is reckoned by 
aid of the Table for three temperatures, viz.:— 


Heat. 

i,8oo° C. 

1,900° C. 

2,000° C. i 

! 

2 molecules of nitrogen 

1 molecule of aqueous vapour 

28.46 

23-93 

30.28 

25-83 

1 

32.10 

27.76 

52.39 

56.11 ( ?1 ) 

59-86 (q 2 ) 


The true calorific value of 58.2 lies between the figures 
marked q x and q 2 , and hence the flame temperature 6 must 
be between 1,900 and 2,000 degrees Cent. The difference 
of flame temperature over this small interval of 100 degrees 
may be taken as proportional to the difference of calorific 














CALORIFIC POWER OF FUEL. 


21 I 


value, which is 59.86— 56.11 = 3.75, and therefore 1 calorie 
corresponds with a change of temperature of 1,000+3.75 = 
26.7 degrees. Consequently, the difference between the 
calorific value of 56.11 at 1,900 degrees and the ascertained 
calorific value of 58.2 corresponds with a change of tem¬ 
perature of 58.2 — 56.11 = 2.09 x 26.7 = 56 degrees. There¬ 
fore the temperature of the hydrogen flame is 1,900+56 = 
1,956 degrees Cent. 

The following lists of fuels, liquids, and gases were 
calculated in this manner :— 


Fuels. 

Net Calorific Power. 
B.Th.U. per pound. 

Flame 

Temperature. 
Degrees Cent. 

Solids— 



Oakwood ----- 

7,860 

1,865 

Bohemian lignite 

10,060 

2,020 

Flaming coal from Blanzy 

14,500 

1,990 

Gas-coal from Saarfield - 

14,600 

i, 95 ° 

Rich coal from Treuil 

15 . 45 ° 

2,010 

Anthracite .... 

14,920 

2,030 

Pennsylvanian anthracite - 

14,650 

2,000 

Peat ----- 

10,060 

2,020 

Liquids— 



Ethyl and methyl alcohol 

• •• 

i, 7 °o 

Amyl alcohol - 

... 

1,850 

American crude petroleum 

18,720 

2,000 

American refined petroleum 

18,500 

1,660 (?) 

Gases— 



Hydrogen - - - - 


1,960 

Carbonic oxide - - - - 


2,100 

1,850 

Methane. 


Acetylene. 


2 , 35 ° 

Coal-gas. 


1,950 

Water-gas j. 


2,000 


Journal of Gas Lighting, vol. Ixxxv., p. 503. 


This undoubtedly proves that the composition of the 
gas and the specific heat of its constituent will be of more 
importance in the future than at present, especially if 














212 


PHOTOMETRY AND GAS TESTING. 


calorific value is going to be taken account of. One 
method of great assistance is to give both the gross and 
net calories, as the bigger the difference the lower the 
flame temperature. 

Another interesting experiment on this matter is that 
carried out by Professor V. B. Lewes. He pointed out in 
his Cantor Lectures that he had obtained over 19 candles 





per cub. ft. with uncarburetted water-gas. The water-gas 
was purified from carbon dioxide, and had a calorific value 
of 81.86 calories gross and 74.66 net. This gas of 81.86 
calories, or 325.7 B.Th.U., gave 19.38 candles per cub. ft. 
of gas consumed; the mean of four readings being 158 
candles for a consumption of 8.15 cub. ft. of uncarburetted 
water-gas at a pressure of 1.3 in. The chimney employed 
was 5 in, by 2 in., which gave better results than a larger 















GAS ANALYSIS. 213 

one, it being evident that under these conditions one got 
just the right air supply. 

Coming to the question of flame temperature one finds 
coal-gas gives a flame the temperature of which is some¬ 
where about 1,960 degrees Cent, and water-gas, as per 
above Table, is 2,000 degrees Cent. 

Gas Analysis.—It is only our purpose to treat of 
the partial analysis of gas, and for the complete analysis, 
which is a work in itself, the reader is referred to Hempel, 
“ Gas Analysis,” pp. 44-69. 

The figure opposite shows the improved form of Biinte 
gas burette. In the use of these burettes to arrive at any 
results worth considering requires a good deal of constant 
practice. In unskilful hands, to say the least, the results 
are bound to be wrong or incorrect in some way or 
other. 

With these burettes one is capable of doing a fair 
analysis of a sample of gas, including:—Benzene vapours, 
carbon dioxide (C 0 2 ), heavy hydrocarbons (unsaturated, 
such as ethylene, &c., group C n H lu2 ), oxygen, carbon mon¬ 
oxide, hydrogen. 

The marsh gas or methane can only be satisfactorily 
analysed in Hempel explosion pipette. 

The apparatus is fitted up as above, and the following 
is a description and method of using it:— A and B are two 
burettes fitted with three-way cocks, each graduated into 
i c.c., and capable of holding 100 c.c.; C, a one-gallon 
tabulated bottle serving as water reservoir ; and D, aspirator. 

The burette is filled by opening the stop-cocks g and 
k, and allowing water to enter from the bottle C until it 
nearly fills the funnel d. The stop-cock is then closed and 
the indiarubber tube detached from the bottom of the 
burette. The longitudinal bore of the stop-cock k is now 
connected at a with the tube supplying the gas to be 
examined, and the gas aspirated into the burette by 
running the water out of the burette by means of the stop- 


214 


PHOTOMETRY AND GAS TESTING. 


cock^*. Rather more than ioo c.c.—about 108 c.c.—of gas 
should be allowed to enter the burette. This is then 
adjusted nearer the zero mark. By means of the bottle 
C sufficient water is forced into the burette through cock 
g to compress the gas, then cock g is closed and cock k is 

opened. The gas 
being under pres¬ 
sure will bubble out 
through the water in 
d. The funnel d is 
now filled up to the 
mark, stop-cock d is 
shut, and the burette 
is detached from 
stand and placed in 
a jar of water at the 
temperature of the 
room. The stop-cock 
k is now opened and 
burette left in the 
water for a sufficient 
time for the gas to 
become the same 
temperature, say ten 
minutes. The stop¬ 
cock k is now closed 
and the burette taken 
out (avoid handling 
as much as possible, 
only handling by the 
extreme ends) and 
placed in stand. The true volume of gas in burette is now 
read, say 104.6 c.c. 

It is not usual to estimate benzene vapour in a Blinte 
burette, but this can be done as follows :—The tube c of 
the aspirator D is connected to the cock g, suction applied 
at N. Stop-cock g is now opened and the water in the 



illlllllllllllli} 

Fig. 53.—Bunte Burettes and Stand. 





















GAS ANALYSIS—BENZENE. 


2T5 


burette is aspirated out as low as possible without un¬ 
seating the burette. The stop-cock is then closed, the 
tube removed, and the end of the burette dipped into a fair 
sized porcelain crucible containing ethyl alcohol (absolute). 
On opening the stop-cock g (the burette being under 
vacuo) a quantity of the solution will rise in the burette. 
(Care must be taken that the bottom of the burette is 
always immersed in the solution, for if the faintest trace of 
air enters the experiment is spoilt.) When the solution 
has entered the burette the stop-cock is closed, the burette 
taken from the stand, and the hand of the operator being 
placed firmly over d y the contents of the 
burette are shaken up with the solution. 

After shaking, replace burette and open 
stop-cock k . The water in d will now 
flow into burette. After allowing the 
water to run through burette until all 
the solution used has been displaced, the 
stop-cocks k and g are now closed, and 
the water level in d made up to the 
mark. The burette is now placed in the 
cylinder of water for ten minutes, the 
stop-cock k being opened. At the end 
of this period the stop-cock k is closed 
and the volume of water in burette read fig. 54-—Cooling Jail 
off. The decrease in volume of gas or 
increase in the water volume gives the amount of benzene 
vapours in the quantity of gas taken ; this is easily calcu¬ 
lated to percentages. 

The next determination is for carbonic acid (C 0 2 ). 
The same procedure is gone through, but the solution used 
for absorbing the C 0 2 is strong caustic potash (1 part 
KHO to 2 parts H 2 0 ). 

After the cooling of burette the difference between the 
volume now observed and that at the close of the last 
reading will give the amount of C 0 2 in the quantity of gas 
taken; this is corrected to percentage. The next absorption 






















216 


PHOTOMETRY AND GAS TESTING. 


is for heavy hydrocarbons. Exactly the same procedure is 
gone through, but the absorbing agent is a solution of 
bromine. After agitating the gas with bromine great care 
must be taken in opening the stop-cocks. The best method 
is to put a porcelain basin under the burette and seal the 
end, and open cock g if the bromine vapour has caused a 
pressure in burette. This will prevent any loss which 
would occur if stop-cock k was opened first. Stop-cock k 
is now opened and a little potash added to absorb the 
bromine vapour, afterwards washing through with water, 
cooling, &c., as before. The difference in volume gives the 
unsaturated hydrocarbons in the gas. 

The next absorbing is for oxygen ( 0 2 ). The same 
procedure is gone through, the reagent in this case being 
pyrogallic acid, followed into the pipette by eight times its 
volume of strong KHO. This solution should not be 
mixed outside the burette. Many operators mix the pyro 
and KHO, and then add to burette; this method is not 
advisable. The difference in volume gives the 0 9 in 
the gas. 

The next constituent to be estimated is the carbonic 
oxide (CO). The same procedure is again gone through, 
but the reagent used being a hydrochloric acid solution of 
cuprous chloride, the difference in volume gives the volume 
of CO in volume of gas taken. 

When estimating for hydrogen and carbonic oxide in a 
sample of gas these are most conveniently estimated by 
combustion, as under :— 

After estimating the oxygen, it is now necessary to mix 
the gas with an excess of air, but as the burette would not 
hold sufficient air to combine with the whole of the gases 
generally present, it is found necessary to expel a portion 
and work on, say, half the volume. The air is admitted by 
placing cock k in communication with the burette, opening 
the pinch-cock at a, and allowing the water to flow out at 
g. This should be continued until the water level is such 
that a sufficiency of air has been admitted, when the cock^- 


GAS ANALYSIS—HYDROGEN. 


217 


and the pinch-cock a are closed, and the contents of the 
burette cooled, &c., as before. The contents of the burette 
are now well shaken up, and after allowing to stand, the 
reading is taken. 

Connection is then made between the burettes A and B 
by uniting the two at the indiarubber a and b by means of 
a piece of combustion tubing containing a small coil of 
palladium wire, the burette B having been previously filled 
with water. The palladium wire in the combustion tube 
should be brought to a red heat by means of a Bunsen 
burner, and the gas in the burette A is caused to pass over 
the heated wire into burette B by opening g and h and 
connecting water supply from C with the bottom of burette 
A. When all the gas from A has passed over (shown by 
the burette being full of water) the operation is reversed, 
the gas being again collected in A. It is then cooled as 
before, water level in cup d adjusted, and the volume read 
off. A solution of caustic potash is then added as in 
the manner described for the estimation of C 0 2 , and the 
diminution in volume noted. 

Before working out the calculation it is necessary to 
notice what action takes place during the combustion. 
The gases to be dealt with (or furnace gases) are hydrogen, 
carbonic oxide, and nitrogen mixed with an excess of air. 
By passing over the red-hot palladium wire the oxygen of 
the air combines with carbonic oxide to form carbonic 
anhydride (CO-f-O = C 0 2 ), and with the hydrogen to form 
water (H 2 + 0 = H 2 0 ), the nitrogen of course not being 
affected. Now supposing that after igniting the gases and 
treating the residue with caustic potash a diminution in 
volume of 12 c.c. was observed, this would be equal to 
12 c.c. of CO, for each volume of CO produces an equal 
volume of C 0 . 2 , and as only half the original volume taken 
was used, the result must be multiplied by two to give the 
true percentage of CO. 

Supposing, also, that after ignition, but before treatment 
with KHO, there was a diminution in the volume of 12 c.c., 


2 18 


PHOTOMETRY AND GAS TESTING. 


this would be due partly to the combination of the hydro¬ 
gen with the oxygen, and partly to the combination of the 
carbonic oxide with the oxygen. 

The CO would require half its volume, or 6 c.c. of the 
oxygen, therefore, deducting this from the 12 c.c. due to the 
combustion, we have 6 c.c. as the resultant due to the 
combination of the hydrogen with the oxygen. Now 
hydrogen combines with oxygen to form water in the 
proportion of two volumes to one, therefore on multiplying 
6 c.c. by § we have 4 c.c. as the number of c.c. of hydro¬ 
gen, and this multiplied by 2 gives 8 c.c. as the percentage 
of hydrogen. The nitrogen is always calculated by 
difference. 


Specific Gravity of Gases.—There are numerous 
apparatus for the determination of the specific gravity of 
gas. They are Bunsen Effusion Test, Letheby Specific 
Gravity Globe, Schilling Diffusion Test, Lux Balance, 
and Simmance-Abady Specific Gravity Bell. 

Bunsen Effusion Test .—This apparatus is based on 
the fact that gases issuing under similar conditions of 
pressure from a given hole in a metallic plate flow through 
it at rates which vary inversely as the square roots of their 
densities. The time taken by a given volume of gas to 
pass through a small (-g^ in. in diameter) aperture in a 
platinum plate, and also the time taken for the same 
volume of gas (such as air) of unit density to pass through 
under similar conditions. Then if T seconds be the time 
taken by the first gas, and T x seconds the time taken by 
the second gas (the density of which is unity), the density 


T 2 

of the first gas is equal to ~--. The apparatus consists of a 

1 

piece of glass tube with platinum foil. There is a line 
scratched on this tube (which is similar to a burette turned 
up), and inside is a float which has two marks on it, 
one at the top end and the other at the bottom. The tube 
is filled with gas and inverted into a trough containing 


SPECIFIC GRAVITY OF GASES. 


219 


mercury, the tube being firmly clamped down into its 
position. The float is now entirely below the mercury. 
The stop-cock is now opened, and the gas being under 
pressure passes out through the orifice in the platinum foil. 
The surface of the mercury is carefully observed through 
a telescope placed level with it. As soon as the upper 
black line on the float appears the clock or stop-watch is 
started, and as soon as the second line appears the stop¬ 
watch is stopped. We now have the time taken by a fixed 
volume of gas to pass through the orifice. The tube is 
next filled with dry air and the operation repeated. 

Example — 

Time dried gas occupied in passing through orifice = 140 seconds. 
>> jj ‘dr >j >) j) = 220 ,, 

220)1,4oo(.636 .636 

.636 

.404496 sp. gr. 



FrG. 55 . —Letheby Specific Gravity Globe. 


Letheby Specific Gravity Globe for determination of gas 
by direct weighing, requires an absolutely correct balance 
and considerable skill on the part of the operator. 

Schilling Diffusion Test .—N. H. Schilling has proposed 
a modification of Bunsen effusion test. The tube is larger 
and the water takes the place of mercury. 

F. Lux Gas Balance shows the specific gravity of gas 
passing through a globe by the indications of a pointer and 
a rider on the beam. The balance is contained in a glass 
case provided with adjusting screws and spirit level. The 
front part of the case is made to swing down, so that the 
whole is easily accessible. The beam of the balance swings 





220 


PHOTOMETRY AND GAS TESTING. 


on agate bearings, and on either side small ivory cups 
filled with mercury are attached by means of brackets. 
These brackets or outer pillars are attached to gas pipes 
underneath the balance, and terminate on the left side in 
two stop-cocks. The handle of the balance is on the right- 
hand side. The beam terminates in a fine steel pointer, 
which moves over a quadrant scale placed parallel to the 
pillar by a long bracket. The beam is graduated into a 
hundred divisions, with a notch at 
every fifth, and marked at every tenth 
division, beginning at the centre of the 
beam with the figure o.o, o.i, and so on 
up to i.o. 

The quadrant scale is divided into 
forty-five divisions, the one in the 
centre being marked o.o, while every 
tenth division on either side is marked 
o.i and 0.2 respectively. Above the 
zero there is a plus sign ( + ), and below 
a minus sign ( —). 

The balance must be placed on a 
very firm base, and must not be ex¬ 
posed to sunlight or any variation in 
temperature, and must be exactly level. 

In performing test the mercury is 
first poured into ivory cups and the 
beam placed on its bearings, then the 
nickel rider is placed in the notch 
marked i.o. If the balance is released, 
the pointer should exactly indicate zero on the quadrant 
scale, if not, this may be attained by means of the hori¬ 
zontal adjusting screw fitted to the centre of the beam. 
The rider is then shifted to 0.8 on the beam, and if the 
balance is properly sensitive each degree on the beam 
should correspond to one degree on the quadrant scale, 
the index should therefore point to plus 0.2 on the 
quadrant (0.8 +0.2= 1.0). 



Fig. 56.—Schilling’s 
Specific Gravity 
Diffusion Test. 












F. LUX GAS BALANCE. 


221 


In passing a gas into the apparatus the rider is placed 
on a figure near to the specific gravity expected, i.e., in the 
case of coal-gas the rider would be placed at 0.5. The 
stop-cock should be so adjusted that nearly all the air will 
be expelled (under a pressure corresponding to about 25 
mm. water column) after two or three minutes, and 
after five minutes the apparatus will therefore be filled 
with pure gas. 

In the case of coal-gas, suppose, now, on the beam 
being released the index records +0.02 on the quadrant, 



Fig. 57.—F. Lux Gas Balance. 


the specific gravity would therefore be 0.5 +0.02 = 0.52. If, 
on the other hand, the index moves to —0.04, this would 
give the specific gravity as 0.5—0.04 = 0.46. 

The quadrant scale has twenty-two divisions on either 
side of the zero; one can command, with the rider in this 
one position (0.50), a range of specific gravity greater than 
any coal-gas would require. 

To determine the specific gravity of gases heavier than 
air, the rider is set before starting on the division zero, the 
pointer likewise being adjusted to indicate zero, the figure 
1.0 should then be added to the value found. 










































222 


PHOTOMETRY AND GAS TESTING. 


Simmance-Abady Portable Specific Gravity Bell , con¬ 
sisting of a small water tank in which a bell is suspended 
from a balance beam. The crown of the bell is drawn out 



Fig. 58.—Simmance-Abady Specific Gravity Bell. 


so that a stand pipe may be brought well up above the 
water line, although the bell itself is submerged up to the 
crown. The apex of the upper crown is formed of a small 






SPECIFIC GRAVITY BELL. 223 

silver plate in which a very fine effusion hole is drilled, and 
this is covered by a protective cap. Extended from the 
beam is a fine pointer, indicating upon a plate marked 
with two divisions. At the inlet to the stand pipe is a two- 
way cock for gas and air, or blow-off; the gas way to be 
connected by flexible or other tubing to the gas service, 
while the air way is free. An extra degree of exactitude is 
provided if the air is brought through caustic potash so as 
to absorb its C 0 2 . A reliable minute clock showing half- 
seconds with start, stop, and set to zero, is fixed to the 
tank. 

To make a Test .—Level the apparatus by screw, seeing 
that the bell hangs centrally in tank. The bell by its 
weight is normally submerged, the tank being filled with 
water just to cover the dome, and only the small effusion 
chamber filled with air. 

Set clock hand to zero, and move weight to notch at 
outer end of beam and slowly open air-cock, thus filling 
the bell with air and taking the pointer up beyond the 
highest mark on quadrant. 

Close air-cock, hold beam with the left hand, and with 
the right move weight to the next notch, thus allow¬ 
ing the air to escape through effusion hole, and the bell to 
fall slowly. 

As pointer passes the highest mark in the quadrant 
start minute clock, stopping it as the pointer passes the 
lowest mark, and note the time in seconds. Reset clock 
hand to zero, and without moving weight, slightly open 
gas-cock, hold down bell for a second or two (to expel 
the last trace of air through effusion hole), and then release 
same and let bell rise as before. 

When pointer is well above the highest mark on 
quadrant turn off gas-cock. After a second or two the 
confined gas will have attained atmospheric pressure and 
the bell will fall slowly. 

As pointer passes the highest mark on quadrant start 
minute clock, stopping it as the pointer passes the lowest 


224 


PHOTOMETRY AND GAS TESTING. 


mark, and note the time in seconds. Divide the gas time 
squared by the air time squared. 

Example — 

Air time, 59 seconds = 59 s = 3,481. 

Gas time, 41 seconds = 41 2 = 1,681. 

1,68 { ~ 3,481 =0.482 specific gravity of gas. 



CHAPTER XII. 


CARBURETTED WATER-GAS. 

The introduction of carburetted water-gas, and the in¬ 
creasing headway this gas is making of late years, brings 
another raw material under the consideration of the gas 
engineer and the gas chemist’s notice. 

It is not intended to touch on the subject of manufac¬ 
ture, but only to deal with the raw materials from the 
chemist’s point of view. The matter of coke has been 
already mentioned, and the remarks as to a good coke 
apply equally well for oil-gas manufacture as for any other 
purpose. 

In the valuation of oils for gas-making purposes the 
following analyses are usually made :— 

Specific Gravity.—Oil is generally bought by weight, 
and this is calculated from its volume and specific gravity. 
The specific gravity can be roughly estimated by specific 
gravity hydrometer. The specific gravity hydrometer can 
now be bought divided into two from 700 to 2,000 degrees. 
These hydrometers only give one the specific gravity 
roughly, and when accuracy is desired the specific gravity 
bottle, as shown in figure, which consists of a glass bottle 
holding 50 or 100 grams of distilled water at 60 degrees 
Eahr., and the neck is fitted with a perforated stopper, en¬ 
abling the bottle to be exactly filled with the liquid with 
the total expulsion of all air bubbles. The oil or liquid 
under examination is brought exactly to the temperature 
of 60 degrees Eahr., the bottle is filled with the liquid, and 


226 


CARBURETTED WATER-GAS. 



Fig. 59.—Specific 
Gravity Bottle. 


(I 


the stop dropped into its place, with the result that the 
liquid will then entirely fill the bottle and the perforation 
in the stopper, and any excess will flow out of the top of 
the stopper. The bottle is now wiped 
with a clean dry cloth, the top of the 
stopper being brushed gently with the 
hand so that nothing will be absorbed 
from the bottle, and the level of the 
liquid will not be lowered. 

The bottle is now weighed, and as 
the bottle is supplied with a counter¬ 
poise weight, the 
weight can be read 
direct. This weight 
divided by the weight 
of water contained in the bottle (viz., 50 or 
100 grams, whichever may be) will give 
the specific gravity of the oil. 

If the temperature is below 60 degrees 
Fahr., the bottle can be held in a vessel of 
water at a higher temperature, while if 
the temperature is above 60 degrees Fahr. 

(as in the warm weather) it may be re¬ 
duced by means of a freezing mixture, 
such as adding a few crystals of am¬ 
monium chloride, or sodium thiosulphate, 
in water. 

Sometimes it is found inconvenient to 
cool an oil to the exact temperature, then 
the specific gravity of an oil may be cor¬ 
rected to that temperature by means of 
the coefficient of expansion of the oil, 
which in the usual cases met with may be 
taken as 0.00036 per each degree Fahr. 

Now the average specific gravity of oil supplied for gas¬ 
making may be taken at about 870 degrees, but supposing 
that the temperature was 70 degrees Fahr. instead of 60 



Fig. 60. — Specific 
Gravity Hy¬ 
drometer. 











ABEL’S FLASH-POINT APPARATUS. 22 J 

degrees Fahr. then the specific gravity at 60 degrees Fahr. 
would be found as follows :— 


70 - 60 = 10 x .00036 == .0036 
.870 

Correct specific gravity at 60 degrees Fahr. =.8736 

The coefficient of expansion is an important factor 
when measuring the quantity 7 of oil in stock ; as the tem¬ 
perature of large quantities of oil 
stored in large tanks varies with 
the atmospheric temperature, it 
is therefore necessary to adjust 
for temperature by this means. 

Flash Point. — The flash 
point of an oil is the tempera¬ 
ture at which the oil commences 
to give off inflammable vapour. 

The lower the flash point of an 
oil, the more danger there is in 
the transportation, storage, and 
use, therefore the determination 
of the flash point is a matter 
of importance. The flash point 
is determined either by means 
of the Abel apparatus or Pensky- 
Marten apparatus. 

The Abel apparatus is shown in illustration, and is the 
instrument described and used by the Board of Trade 
Petroleum Act of 1879. The apparatus consists of an 
outer jacket which is filled with water, the temperature of 
the water being 130 degrees Fahr. at the commencement, 
or, in the case of very low flash oil, cold water is used. The 
oil to be tested is placed in the cup provided, which is in 
the centre of the apparatus, and it is filled so that the top 
of the liquid just reaches the top of the gauge which is 



Fig. 6r.—A bel Flash-Point 
Apparatus. 





















228 


CARBURETTED WATER-GAS. 


fixed within the cup. The lid of the cup with the slide 
closed is then put on, and the cup is placed in position. 
The thermometer in the lid of the cup has been adjusted 
so as to have its bulb just immersed in the liquid, and its 
position must not be altered on any account. 

The test lamp is then placed (or the gas adaption is 
lighted) upon the lid of the cup, the pendulum or lead line 
is set in motion, and the rise of the thermometer in the 
petroleum cup is watched. 

The test flame is applied once 
for every rise of i degree, the slide 
is slowly drawn open while the 
pendulum performs three oscilla¬ 
tions, and is closed during the 
fourth oscillation. Directly a 
“ flash ” or light is noticed inside 
the cup on application of the test 
flame, the temperature of the 
thermometer in the petroleum cup 
gives the temperature at which 
the oil flashes. 

It will be seen that as this 
instrument is water jacketed, it is 
not applicable for the determina¬ 
tion of flash points of oil which 
have a flash point higher than 212 
degrees Fahr. The apparatus used 
in this case is the Pensky-Marten 
flash-point apparatus. This ap¬ 
paratus is shown in the illustration, and is designed for 
the testing of heavy oils (and it is equally suitable for 
testing light oils). It consists of an oil cup, with cover 
fitted with a Centigrade thermometer, with stirrer and 
air bath. 

The bath is heated by a gas flame, and the slow and 
regular heating of the oil is ensured by the jacket of air 
that surrounds the cup. The cup is filled with the oil to 



Fig. 62. — Pensky - Marten 
Flash-Point Apparatus. 



DISTILLATION OF OIL. 


229 


be tested up to the ring inside, and the cover placed in 
position. The cup is then placed in the bath by means of 
the fork provided. 

The thermometer is now inserted in the socket in the 
cover, and the gas burner lighted, the wire gauge being 
interposed if the temperature rises too quickly. The test 
jet is lighted and regulated so that the flame is only the 
size of a small pea. 

During the heating of the oil the stirrer is used from 
time to time. At the increase of each degree the test 
flame is applied by turning the spindle G, which by a suit¬ 
able mechanical arrangement opens a slide in the top of the 
cup, and the test flame is momentarily inserted into the cup. 

Directly sufficient vapour is given off, and on inserting 
the test flame, a flash is noticed, the thermometer being 
read, which gives the flash point of the oil. The appa¬ 
ratus must be kept perfectly clean, as traces of moisture 
interfere with the flash. 

The fractional distillation of an oil affords valuable in¬ 
formation as to its suitability as an enriching agent. The 
apparatus employed consists of a spherical flask fitted to a 
Liebig’s condenser. The flask must have a capacity of 
about twice the volume of oil to be experimented with. 
The procedure is as follows :— 

The spherical flask is weighed empty and the weight 
noted. 10 oz. of the oil to be tested are now measured at 
60 degrees Fahr., and poured into the flask. 

The flask is now weighed, which gives the total weight 
of flask and oil, and deducting the weight of the flask one 
arrives at the weight of the oil taken. 

A Centigrade thermometer which will register up to 
500 degrees Cent, is fitted in the neck by means of a good 
well-fitting cork, through which a hole is bored to take the 
thermometer. The thermometer is fitted in the neck of 
the flask, so that the mercury bulb is on a level with the 
outlet of the flask. 

The neck of the flask is now bound round with asbestos 


230 


CARBURETTED WATER-GAS. 


string and firmly fixed in a clamp on a retort stand, and 
the outlet fixed on to the inlet of the Liebig’s condenser 
as usual. 

The source of heat may be supplied from a Fletcher 
burner, and the heat is regulated to cause the distillate to 
come over in separate drops at fairly regular intervals, 
and as the drops cease to come over, or become irregular, 
the heat is gradually increased. 

The distillates are collected in fractions of I oz., or io 
per cent, of the oil experimented on. The temperature 
recorded by the thermometer is noted directly the contents 
of the flask start boiling, and is again noted directly the 
first drop condenses off the end of the flask, which is easily 
seen in the neck of the inlet of the Liebig’s condenser ; from 
thence the temperature is noted for the completion of each 
ounce until volatile matter ceases to come off, when the 
temperature is increased until nothing but coke is left 
in the flask. The amount of water which comes over 
is particularly noted. A moistened slip of lead paper is 
adjusted at the outlet of condenser, and replaced by a 
fresh piece at the end of each fraction to ascertain the 
varying amount of sulphuretted hydrogen given off at 
various temperatures, which is easily told by the depth of 
colour of the lead paper. 

The flask on cooling is weighed, and the amount of 
coke calculated. 

The specific gravity of each fraction is ascertained and 
calculated into percentage by weight on the original oil. 
This will enable the total weight of the distillates to be 
found, and these, plus the weight of the residue, should very 
nearly total up to the weight of the oil taken, the deficiency 
not being more than i per cent., which is set down to loss 
on distillation. 

Some of the points which indicate the suitability of an 
oil for gas-making purposes are that it should be free from 
water, or only a trace at the most; that the residue left 
after distillation does not exceed i per cent.; and that the 


SAMPLE OF RUSSIAN OIL. 


231 


blackening of a lead paper does not occur until near the 
close of the distillation. The larger the proportion of the 
oil that comes over within a certain range of temperature, 
the more easily will that oil be gasified on the plant, and 
more permanent will be the gas formed from such oil, 
and it should therefore not commence to distil at too low a 
temperature. 

Example — 

Sample of Russian Oil. 

Specific gravity at 6o° Fahr. - - .8742°. 

Flash point.224 0 Fahr. 

Residue - - - - - - 0.12 per cent. 


No. of Fraction. 

Temperature, 

Centigrade. 

Specific 
Gravity at 

60° Fahr. 

Percentage 
by Weight. 

Colour of Distillate. 

Remarks. 

St. to distil. 

Deg. 

66 





F.D.O. - 

146 

. . . 

• • • 

• . . 

... 

I. 

270 

.8384 

9-55 

very pale straw 

SH 2 , very slight 

II. - 

29I 

.8520 

9.71 


brown stain. 

III. - 

300 

.8556 

9*75 


SH 2 , a trace only. 

IV. - 

309 

.8584 

9.78 

» >) 

» 

V. - 

311 

.8620 

9.82 

5 » 

)> » 

VI. - 

330 

.8650 

9.85 

It '!') 

)> >> 

VII. - 

335 

.8704 

9.92 

straw 

SH 2 , very slight 

VIII. 

365 

.8744 

10.00 

darker straw - 

stain. 

SH 2 ,heavierstain. 

IX. - 

388 

.8836 

10.10 

» )> 

» >» 

X. - 

419 

.8968 

10.25 

reddish brown- 

SH 2 , very heavy 

Residui 

a 


0.12 


black stain. 

Loss on distillation 

1.15 


... 




100.00 

... 

... 


Water, nil. SH 2 , very mild throughout distillation. Oil of good 
body and clear appearance, with amber colour, blue fluorescence by 
reflected light. 


















232 


CARBURETTED WATER-GAS. 



Sample of American Oil. 

Specific gravity at 6o° Fahr. - - .8633°. 

Flash point.146° Fahr. 

Residue.0.62 per cent. 


No. of Fraction. 

Temperature, 

Centigrade. 

Specific 
Gravity at 

60° Fahr. 

Percentage 
by Weight. 

Colour of Distillate. 

Remarks. 

St. to distil. 

Deg. 

58 





F.D.O. - 

96 

• • • 

. . . 


. . . 

I. 

284 

.8092 

9-37 

pale straw 

SH 2 , very heavy, 

II. - 

310 

.8352 

9.67 

11 

dark brown stain. 

11 11 

III. - 

326 

.8424 

9.76 

11 

J1 11 

IV. - 

342 

.8492 

9.84 

11 

11 11 

V. - 

356 

.8540 

9.89 

straw 

11 11 

VI. - 

370 

.8608 

9-97 

n 

11 ** 

VII. - 

384 

.8648 

10.01 

11 

11 11 

VIII. 

402 

.8716 

10.09 

darker straw - 

11 11 

IX. - 

420 

.8800 

10.19 


11 11 

X. - 

425 

e 

.8832 

10.23 

reddish brown 

11 11 

Residu 

- 

0.62 

... 


Loss on distillation 

0.19 

... 





100.00 

... 

... 


Water, nil. SH 2 , heavy throughout distillate. Oil of a thin body 
and opaque appearance, slight greenish fluorescence by reflected light. 


The foregoing example shows the results of a distilla¬ 
tion test of a Russian and an American oil. 

The specific gravity of the fractions is ascertained by 
weighing them in a very small gravity bottle, as described 
before. 

The percentage by weight is arrived at by dividing the 
specific gravity of the fraction by the original specific 
gravity of the oil. 
















COMPOSITION AND VALUATION OF OIL. 233 
Example — 

8633).8 o 92 o ( 9 . 3 7 

77697 

• 3 22 3 ° 

25899 

.63310 

In a paper entitled “ Composition and Valuation of Oils 
used for Gas Making,” by Messrs Raymond Ross and 
Leather, read at a meeting of the Society of Public Analysts, 
on 14th June 1906, the authors made classical researches on 
the composition of petroleum from various sources, and 
they gave some account of these investigations carried out 
on various petroleums, and a description of some of the 
few compounds isolated frorti them. They ascertained the 
nature of some principal constituent hydrocarbons, and 
then proceeded to carbonise samples of pure hydrocarbons 
representative of these classes, with the object of ascertain¬ 
ing to what extent these hydrocarbons contributed to the 
gas-making value of an oil. The hydrocarbons specially 
investigated were those containing eleven carbon atoms in 
the molecule undecane, the eleventh hydrocarbon of the 
paraffin series, and is representative of the principal con¬ 
stituent hydrocarbons of Pennsylvanian petroleum. The 
corresponding hydrocarbon of the olefine series is undecy- 
lene, and this was taken as representative of the principal 
hydrocarbons occurring in Scotch gas oil. Decahydro- 
naphthalene was taken as the hydrocarbon representative 
of the chief constituents of Texas gas oil. 

Another hydrocarbon was tetrahydronaphthalene, oc¬ 
curring in Borneo, and to a less extent in other petroleums. 

The following Table gives the constants obtained for 
pure hydrocarbons:— 


234 


CARBURETTED WATER-GAS. 


Table of Constants obtained for Pure Hydrocarbons. 


Name. 

Boiling 
Point. 
Deg.Cent. 

Specific 

Gravity, 

i5/i5- 

N a 

Specific 

Refractory 

Power. 

Valuation 

Figure. 

Undecane - 

Undecylene- 

Decahydronaphthalene 

Tetrahydronaphthalene 

Hexahydrocymene 

194 

193 

172 

205 

l6l 

.746 

-773 
•843 
-9 77 
.783 

I.4182 

1-4332 

1.4507 

1.5712 

I-4323 

.560 

.560 

•534 

.584 

.552 

18,400 

15,961 

n,373 

1,829 


In Pennsylvanian oil the constituents are chiefly 
paraffins, but olefine and paraffinoid bodies also occur. 
In Caucasian oil the constituents are mainly paraffinoid 
hydrocarbons or naphthenes. In Texan oil the constitu¬ 
ents consist of complex ring compounds fully hydro¬ 
genated, and Roumanian oil consists chiefly of unsaturated 
ring compounds. 

The figures given in the next Table were obtained by 
gasifying the oils in a small retort, the temperature being 
controlled by an electrical pyrometer. The oils were 
cracked at different temperatures with a view of ascertain¬ 
ing which gave the highest value in gas. The quantity 
of oil gasified was about 15 c.c. in each case. The hydro¬ 
carbons were absorbed by fuming sulphuric acid. The 
valuation figure is obtained by multiplying the yield of 
gas by the percentage of hydrocarbons found in it. 











AVERAGE OF GASIFICATION RESULTS. 


235 


Averages of Gasification Results. 


Name of Oil. 

Temperature 
of Cracking. 

Cubic Centi¬ 
metres of Gas 
at N.T.P. per 
Cubic Centi¬ 
metre of Oil. 

Hydrocarbons 
absorbed by 
fuming 

h 2 so 4 . 

Valuation 

Figure. 


Degrees Fahr. 


Per cent. 



( 1,260 

445.0 

35-8 

15,931 

Pennsylvanian 

{ Moo 

529.9 

30.1 

15,950 


l L 5 io 

563.O 

26.6 

14,976 

ICansa*; 

( 1,260 

438.9 

33-6 

14,747 


\ 1,400 

482.6 

28.4 

13,706 

Russian 

r 1,260 

465.7 

34-2 

15,927 


11,510 

556.0 

22.8 

12,677 


( 1,260 

42Q.O 

31-8 

13,642 

Russian refined - 

\ 1,510 

518.O 

28.4 

14,711 


11,700 

550.0 

21.5 

11,925 


( 1,130 

325.O 

30.1 

9,783 


1 1,260 

388.3 

29.8 

H, 57 I 

Texas - 

{ 1,400 

461.8 

25-3 

11,684 


1,450 

5477 

18.6 

IO,l87 


11,510 

508.8 

21.1 

10,736 


f 1,130 

370.8 

29.8 

11,050 

Californian - 

1 1,260 

529.9 

26.6 

1 4,096 


11,400 

573-9 

25.4 

14,577 


[ 1,130 

301.3 

40.3 

12,083 

Roumanian - 

1 1,260 

388.8 

33-3 

12,947 


) 1,400 

459-7 

28.6 

I 3 U 48 


11,450 

557-0 

20.2 

11,251 

Galician 

1,260 

452.8 

35-5 

16,074 


[ 1,130 

341.8 

34-6 

11,826 

Grosny 


421.9 

34-6 

14,598 


1 1,400 

501.6 

25.8 

12,941 


f 1,260 

301.0 

26.8 

8,067 

Borneo 

\ 1,510 

472.0 

17.0 

8,024 


11,640 

495-0 

15.0 

7,425 


[ 1,130 

364.8 

40.3 

14,701 

Scotch 

■j 1,260 

426.4 

34-2 

14,583 


1 1,450 

491.5 

26.0 

12,780 










236 


CARBURETTED WATER-GAS. 


Bye-product. —The bye-products of carburetted oil-gas 
consist of practically only one, viz., the tar, which is 
called “ Oil-Gas Tar.” The tar when first condensed on 
the plant contains about 50 per cent, or more of water, 
and in the past this quantity of water has been the 
cause of the trouble to dispose of or use this tar in any 
way. Of late years many methods have been tried to 
decrease this amount of water, and if it is left to stand 
in a tank for a sufficiently long time, the water will 
settle out on the top, and the tar can be drawn off 
from the bottom of the tank by means of a flexible 
hose or suction. 

The tar when so treated will contain less than 5 per 
cent, of water, and is useful in many ways, the chief being 
as a fuel for boiler purposes. 

Matthews and Goulden (Gas World , xvi., p. 625) found 
in water-gas tar from Russian oil :— 


Benzene 

- 

1.10 per cent. 

Toluene 

- 

3-83 

*5 

Light paraffins 

- 

8.51 


Solvent naphtha 

- 

17.96 

n 

Phenols 

- 

trace. 


Middle oils 

- 

29.14 

5 j 

Creosote oil - 

- 

24.26 


Naphthalene - 

- 

1.28 


Anthracene (crude) 

- 

°-93 

n 

Coke 

- 

9.80 




96.90 



Although this tar appears to have a certain value which 
one would expect could be utilised by the tar distiller in a 
similar manner to coal-tar, yet they say that the oil-gas 
tar contains so much paraffin that the extraction of any of 
the other constituents is not remunerative. On distilla¬ 
tion of a sample of oil-gas tar, the following results were 
obtained :— 


OIL-GAS TAR. 


237 


Specific gravity at 6o° Fahr. - - 1.0571°. 

Pitch ------- 20.48 per cent. 

Water.2.60 „ 


No. of 
Fraction. 

Tempera¬ 

ture, 

Centi¬ 

grade. 

Specific 
Gravity of 
Fractions. 

Percentage 

by 

Weight. 

Colour of Distillate. 

Remarks. 

F.D.O. 

Degrees. 

46 





I. 

184 

.9020 

8-53 

cloudy reddish 

S Ho, very strong. 

II. 

218 

.9690 

9.16 

cloudy yellow- 

5> 

III. 

250 

.9840 

9 - 3 i 

clearer yellow 

SH 2 , very strong, 

IV. - 

280 

1.004 

9.50 

clear yellow - 

on cooling 
turned nearly 
solid, due to 
naphthalene. 

SHo, very strong. 

V. 

312 

1.020 

9.64 

5> J) 

55 55 

VI. - 

350 

I.O46 

9.89 

clear reddish - 

55 55 

VII. - 

368 

I.050 

9-93 


55 55 

VIII. - 

37 6 

I.067 

10.01 

clear red 

55 55 

Water - 

- 

2.60 



Residue 

- 

20.48 



Loss on distillation 

o -95 





j 100.00 




This example shows about the average, but the quality 
of tar differs considerably according to the oil used, tem¬ 
perature of carburetter, &c. The use of oil-gas tar as a 
fuel for boilers is well known, it gives a good result, and 
when properly burnt, &c., gives no smoke, which is a great 
inducement in some quarters for its adoption. 

In The Surveyor and Municipal County Engineer for 
the 29th June 1906, appears a report on the application of 
oil-gas tar for improving road surfaces. This material was 
found very suitable for the preservation of macadam and 
other roadway and footway surfaces, and for preventing 
the formation of dust, and the penetration of wet into the 
crust of the road. 

The trials were carried out by the Borough Engineer at 
Tunbridge Wells. The roads were first of all swept clean 












238 


CARBURETTED WATER-GAS. 


of all loose dust, &c., and it was found that traffic could 
pass over the road directly afterward, and that therefore 
there was no closing of the road. Oil-gas tar, as proved 
by these experiments, appears to be probably the most 
effective, economical, and most expeditiously applied dust 
preventive treatment yet utilised in a practical way over 
large areas. 


APPENDIX A. 


-♦- 

METROPOLIS GAS. 


NOTIFICATION OF THE GAS REFEREES FOR 
THE YEAR 1907. 

Office of the Metropolitan Gas Referees, 

66 Victoria Street, S.W., 

December 1906. 

Whereas the undersigned have been appointed “Gas Referees” 
under the City of London Gas Act, 1868; The South Metro¬ 
politan Gas Light and Coke Company’s Act, 1869; The Com¬ 
mercial Gas Act, 1875 ; The Gas Light and Coke Company Act, 
1876; The South Metropolitan Gas Light and Coke Company’s 
Act, 1876; The Gas Light and Coke and other Gas Companies 
Acts Amendment Act, 1880; and the London Gas Act, 1905. 

And whereas it is the duty of the said Gas Referees, under 
the same and othei Acts of Parliament, among other things, to 
prescribe and certify the situation and number of the testing 
places, and the apparatus and materials therein, for testing the 
illuminating power, calorific power, purity, and pressure of the 
gas to be provided by the Companies; and the mode to be 
adopted for testing and recording the illuminating power, calorific 
power, purity, and pressure of the gas; and the number of the 
times of testing, except in the case of testings for pressure and 
of testings made under section 5 of the London Gas Act, 1905 : 

Now, therefore, in compliance with the provisions of the said 
Acts, the said Gas Referees do hereby prescribe and certify as 
follows ; that is to say, 

As to the 
Testing Places. 

The testing places shall, for the present, be as follows:— 




240 


APPENDIX A. 


Lor the Gas Light and Coke Company. 

1. At No. 106 Fenchurch Street, E.C. 

2. At No. 93 Aldersgate Street, E.C. 

3. At No. 7 Tudor Street, Blackfriars, E.C. 

4. At No. 123 Ladbroke Grove, Notting Hill, W. 

5. At No. 3 Vincent Terrace, Islington, N. 

6. At No. 1 Carlyle Square, Chelsea, S.W. 

7. At No. 170 Camden Street, Camden Town, N.W. 

8. At No. 14# Graham Road, Dalston, N.E. 

9. At No. 47 Kingsland Road, N.E. 

10. At the Offices of the London County Council, 

Spring Gardens, S.W. 

11. At No. 1 Vinery Villas, North Bank, Regent’s Park, 

N.W. 

12. At No. 116 Lambeth Road, S.E. 

13. At No. 121 Hornsey Road, Holloway, N. 

14. At No. 66 George Street, Hampstead Road, N.W. 

For the Commercial Gas Company. 

1. At No. 6 Wellclose Square, St George’s, E. 

2. At No. 24 Parnell Road, Old Ford, E. 

For the South Metropolitan Gas Company. 

1. At No. 104 Hill Street, Peckham, S.E. 

2. At No. 37 Bedford Road, Clapham Road, S.W. 

3. At No. 1 Stoney Lane, Tooley Street, S.E. 

4. At No. 180 Lewisham Road, Lewisham, S.E. 

5. At No. 107 Blackfriars Road, S.E. 

6. At No. 211 Burrage Road, Plumstead, S.E. 


As to the 

Service Pipes to the Testing Places. 

The conditions to be observed in connecting the Gas Com¬ 
panies’ mains with the apparatus in the testing places and in 
providing for shutting off the gas in case of emergency are 
prescribed by section 8 of the London Gas Act, 1905. 

If obstruction of the service pipe is found, or if there is reason 
to think that the quality of the gas is suffering from any change 
occurring within the service pipe, the service pipe may be washed 



STANDARD LAMP. 


241 


out in the presence of and by arrangement with the Gas Examiner, 
either with hot water alone or with any usual solvent such as 
benzol, naphtha, or petroleum, but the use of such solvents is to 
be followed by a washing with hot water. In every case where 
the service pipe is washed out the Gas Company shall send a 
letter to the Gas Referees explaining why the washing was 
considered necessary. The Gas Companies may, if they think 
fit, provide a tap and funnel in any testing place for the purpose 
of such washing out. 

No testing for illuminating power is to be made until after 
the lapse of an hour since the last washing out. 


As to the 

Standard Lamp to be used for Testing Illuminating 
Power. 

The standard to be used in testing the illuminating power 
of gas shall be a Pentane 10-candle Lamp which has been 
examined and certified by the Gas Referees. A description of 
the lamp is given in Appendix A. The residue of pentane in 
the saturator shall, at least once in each calendar month, be 
removed, and shall not be used again in any testings. 

The pentane to be used in this lamp shall be prepared as 
described in Appendix B, and shall show when tested the 
properties there specified. 

All pentane provided by the Gas Companies will be examined 
and certified by the Gas Referees, and will be sent to the testing 
places in cans, which have been both sealed and labelled by 
them; and no pentane shall be used in the testing places other 
than that which has been thus certified. 

The procedure to be followed in the issue of pentane to the 
testing places is described in Appendix C. 


As to the 

Times and Mode of Testing for Illuminating Power. 

1. Test mgs with the Metropolitan Argand Burner , No. 2. 

The testings for Illuminating Power made with the Standard 
Argand shall be three in number daily. “ The tests for illumin¬ 
ating power shall be taken at intervals of not less than one hour.” 
“The average of all the testings at any testing place on each 

Q 




242 


APPENDIX A. 


day of the illuminating power of the gas supplied by the Company 
at such testing place shall be deemed to represent the illuminat¬ 
ing power of such gas on that day at such testing place.” (Gas¬ 
light and Coke and other Gas Companies Acts Amendment 
Act, 1880, sections 7 and 8.) 

But “ If on any one day the gas supplied by the Company 
at any testing place is of less illuminating power to an extent 
not exceeding one candle than it ought to be, the average of all 
■ the testings made at such testing place on that day and on the 
preceding day and on the following day shall be deemed to 
represent the illuminating power of the gas on such one day at 
such testing place.” (London Gas Act, 1905, section 4 (3).) 

The gas supplied by the Gas Light and Coke Company is 
required to have an illuminating power of 16 candles, and the 
gas supplied by the South Metropolitan Gas Company and by 
the Commercial Gas Company an illuminating power of 14 
candles. (London Gas Act, 1905, section 4 (1), (2).) 

The Photometer to be used in the testing places shall be the 
Table Photometer described in Appendix D. The air-gas in the 
lamp is to be kept burning so that the flame is near its proper 
height for at least ten minutes before any testing is made. At 
the completion of every testing the air-gas is to be turned off; 
but if the interval between two testings does not much exceed 
one hour and the Gas Examiner is present during the interval, 
he may, instead of turning it off completely, turn it down low. 

The Argand Burner attached to each Photometer shall be a 
standard burner called the Metropolitan Argand Burner, No. 2, 
which has been devised by Mr Charles Carpenter. A description 
of the burner is given in Appendix E. No Argand Burner shall 
be used for testing the illuminating power of gas that does not 
bear the lead seal of the Gas Referees. 

A clean chimney is to be placed on the burner before each 
testing, and care should be taken that the glass does not become 
dimmed by the smoking of the flame. 

The gas under examination is to be kept burning, at about 
the usual rate, for at least fifteen minutes before any testing is 
v made; the damper shall not be in action during this interval. 
No gas shall pass through the meter attached to the Photometer 
except that which is consumed in testing or during the intervals 
between the testings made on any day, and that which is used 
in proving the meter. (See p. 250 and Appendix N.) 

The paper used in the photoped of the Photometer shall be 
white in colour, unglazed, of fine grain and free from water marks. 
It shall be as translucent as is possible consistently with its being 
sufficiently opaque to prevent any change in the apparent relative 


TIME AND MODE OF TESTING. 


243 


brightness of the two portions of the illuminated surface when 
the head is moved to either side. This paper should, when not 
in use, be covered to protect it from dust; and if it has been in 
any way marked or soiled a fresh piece is to be substituted. 

Each testing shall be made as follows:— 

The index of the regulating tap shall be so adjusted that the 
meter hand makes one complete revolution in not less than 59 
or more than 61 seconds. The damper for regulating the air- 
supply to- the burner shall be screwed upwards until the flame is 
on the point of tailing above the chimney and then immediately 
be turned down only so far as to ensure that the flame burns 
without any smoking. The connecting rod shall now be pushed 
to and fro by the Gas Examiner until the illumination of the 
photoped by the two sources of light is judged to be equal. A 
balance is best attained by making small alternations of decreasing 
amplitude rather than by a very slow movement in one direction 
only. The reading on the photometric scale shall be noted. 
This observation is to be made four times in all, and the mean 
of the results taken. The time that the meter hand takes to 
make exactly two revolutions shall then be observed by the aid 
of a stop clock or stop-watch. The mean of the four readings 
of the photometric scale shall be multiplied by the number of 
seconds in the time recorded and by the Aerorthometer reading 
and divided by 120. The quotient is the illuminating power. 

If the gas is so rich that it cannot be made to burn at the 
prescribed rate without tailing above the chimney or smoking, 
or if the burner cannot be pushed far enough away to produce 
equality of illumination on the photoped, the rate must be 
reduced until the flame burns properly within the chimney or 
a balance is produced when the burner is at the far end of the 
slide. In all other respects the testing and calculation shall be 
made as described. 

If, in very exceptional circumstances, the Aerorthometer 
scale or the table does not include the conditions that are met 
with, the Gas Examiner shall, in calculating the illuminating 
power, use the formula printed below the table. 

Each testing place must be provided with a standard clock 
that will go for a week without re-winding. 

The Gas Examiner shall, at least once a week, compare the 
stop-clock in the testing place with the standard clock or with 
his watch. 

The Gas Examiner shall enter in his book the particulars 
of every testing of illuminating power made by him at the testing 
places, during or immediately after such testing; and in the case 
of any testing which he rejects he shall also state the cause of 


244 


APPENDIX A. 


rejection. No testing is to be rejected on the ground that the 
result seems improbable. 


2. Testings with the Standard Flat Flame Burner. 

The testings for illuminating power made with the flat flame 
burner shall be made at such times as the Controlling Authority 
shall direct. The burner shall be Bray’s “No. 7 Economiser” 
fitted over a Bray’s “ No. 4 Regulator,” as described in Appendix 
D. The testings made with it shall be conducted in the same way 
as those with the Argand; but when a testing with the Argand 
has been made immediately before, the testing with the flat flame 
burner may be made when the gas has been burning through it 
at the usual rate for five minutes. A new burner shall be used 
every week. 

If the gas is so poor that the burner cannot be brought near 
enough to produce equality of illumination on the photoped, the 
rate of consumption must be increased, until a balance is produced 
when the burner is at the near end of the slide. In all other 
respects the testing shall be carried out as described. 


As to the 

Times and Mode of Testing for Sulphuretted 
Hydrogen. 

“ The gas supplied by the Company shall not exhibit any trace 
of sulphuretted hydrogen when tested in a mode to be from time 
to time prescribed and certified by the Gas Referees for testing and 
recording the presence of sulphuretted hydrogen, which mode shall 
not be more stringent than the mode prescribed in Schedule A of 
the Gasworks Clauses Act, 1871.” (London Gas Act, 1905, sec¬ 
tion 6.) 

The apparatus to be used in testing gas for the presence of 
sulphuretted hydrogen is figured in Appendix H. The gas as it 
leaves the service pipe shall be passed through the glass vessel in 
which are suspended slips of bibulous paper which have been re¬ 
cently moistened by dipping them in a solution consisting of 6.5 
grams (100 grains) of crystallised acetate of lead dissolved in 100 
cubic centimetres of water. 

One testing shall be made daily. 

In making the testing, gas shall be turned on to the apparatus, 
and lit at the burner as soon as the air has been swept out. When 
the gas has burnt for three minutes it is to be turned off, and 
one of the slips of paper is to be compared with another similar 




SULPHUR COMPOUNDS. 


245 


slip which has not been exposed to the gas. The gas is to be 
taken as exhibiting a trace of sulphuretted hydrogen if the slip of 
paper which has been exposed to it is unmistakably the darker 
of the two. 

In this event two of the test-slips which have been exposed to 
the gas shall be placed in a stoppered bottle and kept in the dark 
at the testing place; one of the remaining slips shall be forwarded 
with each daily Report (Appendix O), and the comparison slip 
shall be retained by the Gas Examiner for the use of the Chief 
Gas Examiner. 

The Gas Examiner in making his return shall write either 
“present” or “absent” as the case may be. 


As to the 

Mode of Testing for Sulphur Compounds other than 
Sulphuretted Hydrogen. 

This testing shall be made on such days as the Controlling 
Authority shall direct. A description of the apparatus to be em¬ 
ployed is given in Appendix K. It is to be set up in a room or 
closet where no other gas is burning. The gas shall pass through 
a meter by reference to which the rate of flow can be adjusted, 
and which is provided with a self-acting movement for shutting 
off the gas when ten cubic feet have passed. 

Pieces of sesqui-carbonate of ammonia, from the surface of 
which any efflorescence has been removed, are to be placed round 
the stem of the burner. The index of the meter is to be then 
turned forward to the point at which the catch falls and will again 
support the lever-tap in the horizontal position. The lever is made 
to rest against the catch so as to turn on the gas. The index is 
turned back to a little short of zero, and the burner lighted. When 
the index is close to zero the trumpet-tube is placed in position on 
the stand and its narrow end connected with the tubulure of the 
condenser. At the same time the long chimney tube is attached 
to the top of the condenser. 

As soon as the testing has been started, a first reading of the 
Aerorthometer is to be made and recorded, and a second reading 
as near as may be to the time at which the gas is shut off. The 
rate of burning, which with practice can be judged very nearly by 
the height of the flame, is to be adjusted, by timing the index of 
the meter, to about half a cubic foot of gas per hour. 

After each testing, the flask or beaker, which has received the 
liquid products of the combustion of the ten cubic feet of gas, 
is to be emptied into a measuring cylinder and then replaced to 



246 


APPENDIX A. 


receive the washings of the condenser. Next the trumpet-tube is 
to be removed and well washed out into the measuring cylinder. 
The condenser is then to be flushed twice or thrice by pouring 
quickly into the mouth of it 40 or 50 cubic centimetres of distilled 
water. These washings are brought into the measuring cylinder, 
whose contents are to be well mixed and divided into two equal 
parts. 

One-half of the liquid so obtained is to be set aside, in case it 
should be desirable to repeat the determination of the amount of 
sulphur which the liquid contains. 

The other half of the liquid is to be brought into a flask, or 
beaker covered with a large watch-glass, treated with Hydrochloric 
Acid sufficient in quantity to leave an excess of acid in the solution, 
and then raised to the boiling point. An excess of a solution of 
Barium Chloride is now to be added, and the boiling continued 
for five minutes. The vessel and its contents are to be allowed 
to stand till the Barium Sulphate has settled at the bottom of the 
vessel, after which the clear liquid is to be as far as possible poured 
off through a paper filter. The remaining liquid and Barium Sul¬ 
phate are then to be brought on to the filter, and the latter is to 
be well washed with hot distilled water. (In order to ascertain 
whether every trace of Barium Chloride and Ammonium Chloride 
has been removed, a small quantity of the washings from the filter 
should be placed in a test tube, and a drop of a solution of Silver 
Nitrate added; should the liquid, instead of remaining perfectly 
clear, become cloudy, the washing must be continued until on re¬ 
peating the test no cloudiness is produced.) Dry the filter with 
its contents, and transfer it into a weighed platinum crucible. 
Heat the crucible over a lamp, increasing the temperature gradually, 
from the point at which the paper begins to char, up to bright red¬ 
ness.* When no black particles remain, allow the crucible to 
cool; place it when nearly cold in a desiccator over strong Sul¬ 
phuric Acid, and again weigh it. The difference between the first 
and second weighings of the crucible will give the number of grains 
of Barium Sulphate. Multiply this number by 11 and divide by 
4; the result is the number of grains of sulphur in 100 cubic feet 
of the gas. 

This number is to be corrected for the variations of temperature 
and atmospheric pressure in the manner indicated under the head 
of Illuminating Power, with this difference, that the mean of the 
first and second Aerorthometer readings shall be taken as the 
reading. 


* An equally good and more expeditious method is to drop the filter with 
its contents, drained but not dried, into the red-hot crucible. 



CALORIFIC POWER OF GAS. 


247 


The correction by means of the Aerorthometer reading may 
be made most simply and with sufficient accuracy in the following 
manner:— 

When the Aerorthometer reading is between .955-.965, 
•9^5-.975, .975--98S, -985-.995, diminish the number of grains 
of Sulphur by 4, 3, 2, and 1 per cent. 

When the Aerorthometer reading is between 995-1.005, no 
correction need be made. 

When the Aerorthometer reading is between 1.005-1.015, 
1.015-1.025, 1.025-1.035, increase the number of grains of Sulphur 
by 1, 2, and 3 per cent. 

Example:— 

Grains of Barium Sulphate from 5 

cubic ft. of Gas - - - 10.4 

Multiply by 11 and divide by 4 - 11 

4)114.4 

Grains of Sulphur in 100 cubic ft. of 

Gas (uncorrected) - - - 28.60 

Add 28.6 x 1 | 7 = ... .57 

Grains of Sulphur in 100 cubic ft. of 

Gas (corrected) - - - -29.17 

The Aerorthometer reading is the reciprocal of the Tabular 
Number. The Gas Examiner shall, not less often than once a 
month, compare the Aerorthometer reading with the reciprocal of 
the Tabular Number deduced from observations of the Barometer 
and Thermometer, and if there is a difference of more than one- 
half per cent, the Aerorthometer is to be readjusted. 


Aerorthometer reading, 
1.018 


Result: 
29.2 grains. 


As to the 

Mode of Testing the Calorific Power of the Gas. 

This testing shall be made on such days as the Controlling 
Authority shall direct. 

The Calorimeter to be used in testing the calorific power of 
the gas shall be one which has been examined and certified by 
the Gas Referees. A description of the Calorimeter is given in 
Appendix L. 

In order to test the gas for calorific power, the gas shall first 
pass through a meter and a balance governor of the same con¬ 
struction as those on the photometer table. It shall then be led 
to the gas inlet in the base of the Calorimeter. The gas shall be 




APPENDIX A. 


248 

turned on and lighted, and the tap of the Calorimeter shall be so 
adjusted as to allow the meter hand to make one turn in from 60 
to 75 seconds. The water shall be turned on so that when the 
regular flow through the Calorimeter has been established a little 
may pass the overflow of the funnel and trickle over into the sink. 
Water must be poured in through one of the holes in the lid until 
it begins to run out at the condensation outlet. The Calorimeter 
may then be placed upon its base. The measuring vessel carrying 
the change-over funnel shown in Figs. 16 and 18, pp. 277 and 278, 
should then be placed in position in the sink so that the outlet 
water is led into the sink. The hot-water outlet tube of the Cal¬ 
orimeter should be above but should not touch the change-over 
funnel. After an interval of not less than twenty minutes the Gas 
Examiner, after bringing the reading glasses into position on the 
thermometers used for measuring the temperature of the inlet and 
outlet w^ter, shall then make the following observations. When 
the meter hand is at 75 he shall read the inlet temperature; when 
it reaches 100 he shall move the funnel so as to direct the outflow 
into the measuring vessel and at the same time he shall start the 
stop-clock or a stop-watch. When the meter hand reaches 25 he 
shall make the first reading of the outlet temperature. He shall 
continue to read the outlet temperature at every quarter turn until 
fifteen readings have been taken. The meter hand will then be at 
75. He shall also at every turn of the meter except the last make 
a reading of the inlet temperature when the meter hand is between 
75 and 100. When the meter hand reaches 100 after the last out¬ 
let temperature has been read, the Gas Examiner shall shift the 
funnel so as to direct the outlet water into the sink again and at the 
same time stop the clock or watch. The barometer and the ther¬ 
mometers showing the temperatures of the effluent gas, of the air 
near the Calorimeter and of the gas in the meter, shall then be 
read. The time shown by the stop-clock shall be recorded. The 
mean of the four readings of the inlet temperature is to be sub¬ 
tracted from the mean of the fifteen readings of the outlet tempera¬ 
ture and the difference is to be multiplied by 3 and by the num¬ 
ber of litres of water collected and the product is to be divided by 
the tabular number. The difference in degrees Centigrade of the 
temperature of the effluent gas and of the surrounding air shall 
be taken, and one-sixth of this difference shall be added to the 
result previously found if the effluent gas is the warmer of the 
two, or subtracted if the effluent gas is the cooler of the two.* 
The result is the gross calorific power of the gas in Calories per 
cubic foot. 


This correction has been found by experiment. 



TESTING PRESSURE. 


249 


In addition to the observations described, the amount of con¬ 
densed water resulting from the combustion of the gas shall be 
measured. For this purpose the condensation water shall be led 
into a flask not less then twenty minutes after the Calorimeter has 
been placed in position. The amount collected in not less than 
thirty minutes shall be measured, the time of collection having 
been accurately noted. 

The number of cubic centimetres collected shall be multiplied 
by the number of seconds in the time indicated by the stop-clock 
and by the number 1.86. The number of seconds in the time 
during which the condensed water was being collected shall be 
multiplied by the tabular number. The first product shall be 
divided by the second. The quotient is to be subtracted from 
the gross calorific power. The difference is the net calorific 
power in Calories per cubic foot. The gross and net calorific 
power in British Thermal Units can be obtained by multiplying 
the corresponding numbers of Calories by 3.968. 

A form on which the Gas Examiner may conveniently set down 
his observations and the whole of the figures needed for the cal¬ 
culation is given at end of Appendix L. The figures in italic type 
are specimen figures, and represent such as might be written by 
the Gas Examiner. 


As to the 

Mode of Testing the Pressure at which 
Gas is Supplied. 

Testings of pressure shall be made at such times and in such 
places as the Controlling Authority may from time to time appoint 
(Gas Light and Coke and other Gas Companies Acts Amendment 
Act, 1880, Section 6). In order to make this testing the Gas 
Examiner shall unscrew the governor and burner of one of the 
ordinary public lamps, and shall attach in their stead a portable 
pressure gauge. In places where incandescent burners are used 
for street lighting, one street lamp in each street or group of streets 
may be provided under the lantern with a branch closed by a screw 
stopper. The Gas Examiner shall in such cases connect the 
pressure gauge by screwing to it an L-shaped pipe fitted with a 
union, by means of which it may be connected to the service pipe 
in the place of the screw stopper. The L-shaped pipe is to be of 
such dimensions as to enable the pressure gauge to be fixed outside 
the lantern but at about the same level as the incandescent burner. 
It should be provided with a tap. 

The gauge to be used for this purpose consists of an ordinary 



250 


APPENDIX A. 


pressure gauge enclosed in a lantern, which also holds a candle for 
throwing light upon the tubes and scale. The difference of level 
of the water in the two limbs of the gauge is read by means of a 
sliding scale, the zero of which is made to coincide with the top 
of the lower column of liquid (see Appendix M). 

The Gas Examiner having fixed the gauge gas-tight, and as 
nearly as possible vertical on the pipe of the lamp, and having 
opened the cocks of the lamp and gauge, shall read and at 
once record the pressure shown. From the observed pressure 
one-tenth of an inch is to be deducted to correct for the differ¬ 
ence between the pressure of gas at the top of the lamp column 
and that at which it is supplied to the basement of neighbouring 
houses. 

The pressure prescribed in the Acts of the three Metropolitan 
Gas Companies is to be such as to balance from midnight to sunset 
a column of water not less than six-tenths of an inch in height, and 
to balance from sunset to midnight a column of water not less than 
one inch in height. 


Meters. 

The meters used for measuring the gas consumed in making 
the various testings shall be wet meters constructed with measuring 
drums which allow one-twelfth of a cubic foot of gas to pass for 
every revolution. A hand is fastened directly to the axle of the 
drum and passes over a dial divided into one hundred equal 
divisions. The dial and hand are protected by a glass. In the 
meter employed in testing the purity of gas the pattern of dial for 
showingthenumberof revolutions and the automatic cut-off hitherto 
in use shall be retained, but in the meters employed for testing illu¬ 
minating power and calorific power, only the dial above described 
is needed. The meters should be provided with Fahrenheit ther¬ 
mometers. The stop-clock may be either attached to the meter 
or separate. 

The meters used for measuring the gas consumed in making 
the various testings shall have been certified by the Referees, and 
shall, at least once in seven days, be proved by the Gas Examiners 
by means of the Referees’ one-twelfth of a cubic foot measure. A 
description of this Instrument, with directions how to use it, is 
given in Appendix N. 

The results of the testings for illuminating power, calorific power, 
purity, and pressure shall be recorded in the form given in Appen¬ 
dix O, and delivered as provided in Section 11 of the Gas Light and 
Coke and other Gas Companies Acts Amendment Act, 1880, and 
in Section 5 (2) of the London Gas Act, 1905. 


THE TEN-CANDLE PENTANE LAMP. 


251 


These regulations shall be in force from the 1st January 1907 
until they are superseded by a subsequent Notification. 



APPENDIX A. 


The Ten-Candle Pentane Lamp. 


Mr Harcourt’s Ten-Candle Pentane Lamp is one in which air 
is saturated with pentane vapour, the air-gas so formed descending 
by its gravity to a steatite ring burner. The flame is drawn into a 
definite form, and the top of it is hidden from view, by a long brass 
chimney above the steatite burner. The chimney is surrounded 
by a larger brass tube, in which the air is warmed by the chimney, 
and so tends to rise. This makes a current which, descending 
through another tube, supplies air to the centre of the steatite 
ring. No glass chimney is required, and no exterior means have 
to be employed to drive the pentane vapour through the burner. 

Figure 1 shows the general appearance of the lamp. The 
saturator a is at starting about two-thirds filled with pentane.* 
It should be replenished from time to time, so that the height of 
liquid as seen against the windows may not be less than one-eighth 
of an inch. The saturator a is connected with the burner b by 
means of a piece of wide indiarubber tube. The rate of flow 
of the gas can be regulated by the stop-cock s 2 , or by checking 
the ingress of air at s r For this latter purpose a metal cone, 
acting as a damper, is suspended by its apex from one end of a 
lever, to the other end of which is attached a thread for moving 
the cone up or down. The lever is supported by an upright arm 
clamped to the upper end of the stop-cock immediately beneath 
the cone. From the top of the lamp 'the thread descends to a 
small pulley on the table, and thence passes horizontally to the 
end of a screw moving in a small block, by turning which the gas 
examiner can regulate the lamp without leaving his seat. It is 
best so to turn the stop-cock s 2 as to allow the flame to be 
definitely too high, but not to turn it full on, before letting down 


* Caution.— Pentane is extremely inflammable; it gives off at ordinary 
temperatures a heavy vapour which is liable to ignite at a flame at a lower level 
than the liquid. The Saturator must never have pentane poured into it when 
in position, if the lamp or the gas of the photometer is alight. 






252 


APPENDIX A. 


the regulating cone to its working position. Both stop-cocks 
should be turned off when the lamp is not alight. 

The chimney tube c c should be turned so that no light 

passing through the 
mica window near its 
base can fall upon 
the photoped. The 
lower end of this 
tube should, when 
the lamp is cold, be 
set 47 millimetres 
above the steatite 
ring burner. A 
cylindrical boxwood 
gauge, 47 millimetres 
in length and 32 in 
diameter, is provided 
with the lamp to 
facilitate this adjust¬ 
ment. The exterior 
tube d communicates 
with the interior of 
the ring burner by 
means of the con¬ 
necting box above 
the tube e and the 
bracket f on which 
the burner b is sup¬ 
ported. A conical 
shade g is provided. 
This should be 
placed so that the 
whole surface of the 
flame beneath the 
tube c may be seen 
at the photoped 
through the opening. 

The lamp should 
be adjusted by its 
levelling screws so 
that the tube e, as 
tested with a plumb-line, is vertical, and so that the upper sur¬ 
face of the steatite burner is 353 millimetres from the table. 
A gauge is provided to facilitate this latter measurement. The 
tube c is brought centrally over the burner by means of the 















































THE TEN-CANDLE PENTANE LAMP. 


253 


three adjusting screws at the base of the tube d. These three 
screws should not be quite screwed up, but only sufficiently so 
to keep the chimney tube central. The adjustment is facilitated 
by means of the boxwood gauge. 

When the lamp is in use the stop cocks are to be regulated 
so that the tip of the flame is about half-way between the bottom 
of the mica window and the crossbar. A variation of a quarter 
of an inch either way has no material influence upon the light of 
the flame. The saturator a should be placed upon the bracket 
as far from the central column as 
the stop at the end will allow. 

If it is found that, after the lamp 
has been lighted for a quarter 
of an hour, the tendency of the 
flame is to become lower, the 
saturator may be placed a little 
nearer the central column. 

To prevent a gradual accu¬ 
mulation of dust in either the 
burner or the air passage, a 
small cover of the size of the 
top of b and shaped like the lid 
of a pill box should be kept 
upon the lamp when not in use. 

The following are the more 
important dimensions on which 
the precision of the lamp de¬ 
pends ; but no departure should 
be made from any of the dimen¬ 
sions as shown by the working 
drawings. All dimensions are 
given in millimetres. 

Saturator, a. —184 x 184 x 
38 deep, inside mea¬ 
surement, with seven 
partitions alternately 
meeting either side and stopping 25 short of the 
opposite side to cause the air to pass eight times across 
the box. These partitions must be soldered to the 
top, not to the bottom of the box. 

Siphon Tube from Saturator .—Outer diameter, 14 (half-inch 
full). 

Indiarubber Tube .—Inner diameter, 13 (half-inch). 

Steatite Burner .—Outer diameter, 24; Inner diameter, 14; 
30 holes, not less than 1.25 or more than T.5 in 



Fig. 2. 

































254 


APPENDIX A. 


diameter. (The holes must be evenly spaced, and in 
any one burner they must not differ from one another 
in diameter by more than .05 millimetre.) 

•Brass Chimney , c.—Outer diameter, 32 ; Inner diameter, 
30; Length, 431. 

Brass Outer Tube , d.— Outer diameter, 52 ; Inner diameter, 
50; Length, 290; Chimney c projects 68 below and 
73 above the tube d. 

Brass Tube , e. —Outer diameter, 25 ; Inner diameter, 23 ; 
Length, 529J; Distance between axis of tube e and 
axis of tubes c and d, 67. 

Shade, g.— Diameter of base, 102 ; Diameter at top, 55 ; 
Height, 57 ; Opening 38 within, 34 without. The 
structure of the actual burner is shown in the sectional 
drawing, Fig. 2. 

The working drawings are kept at the Gas Referees’ office, 
and may be seen, and notes may be made, after permission in 
writing has been obtained from the Referees. 

Note . — The entrance pipe for the pentane, shown dotted in Fig. 2, 
should be more nearly horizontal, as shown in Fig. 1. 


APPENDIX B. 

The pentane to be used in the 10-candle Lamp should be 
prepared and tested in the following manner :— 

Preparation .—Light American petroleum, such as is known 
as Gasoline and used for making air-gas, is to be further rectified 
by three distillations, at 55 0 C., 50°, and 45 0 in succession. The 
distillate at 45 0 is to be shaken up from time to time during two 
periods of not less than three hours each with one-tenth its bulk 
of (1) strong sulphuric acid, (2) solution of caustic soda. After 
these treatments it is to be again distilled, and that portion is to 
be collected for use which comes over between the temperatures 
of 25 0 and 40°. It will consist chiefly of pentane, together with 
small quantities of lower and higher homologues whose presence 
does not affect the light of the lamp. 

Testing .—The density of the liquid pentane at 15 0 C. should 
not be less than 0.6235 nor more than 0.626 as compared with 
that of water of maximum density. The density of the pentane 
when gaseous, as compared with that of hydrogen at the same 
temperature and under the same pressure, may be taken. This 
is done most readily and exactly by Gay Lussac’s method, under 
a pressure of about half an atmosphere and at temperatures 



THE PROVISION OF PENTANE. 255 

between 25 0 and 35 0 . The density of gaseous pentane should 
lie between 36 and 38. 

Any admixture with pentane of hydrocarbons belonging to 
other groups and having a higher photogenic value, such as 
benzene or amylene, must be avoided. Their presence may be 
detected by the following test. Bring into a stoppered 4-oz. 
bottle of white glass 10 c.c. of nitric acid, specific gravity 1.32 
(made by diluting pure nitric acid with half its bulk of water); 
add 1 c.c. of a dilute solution of potassium permanganate, contain¬ 
ing 0.1 gram of permanganate in 200 c.c. Pour into the bottle 
50 c.c. of the sample of pentane, and shake strongly during five 
successive periods of twenty seconds. If no hydrocarbons other 
than paraffins are present, the pink colour, though somewhat 
paler, will still be distinct; if there is an admixture of as much 
as J per cent, of amylene or benzene, the colour will have 
disappeared. 


APPENDIX C. 

The Provision of Pentane for use in the Testing Places. 

The following is the procedure which the Gas Referees have 
arranged with the Gas Companies for the provision and testing 
of pentane:— 

Each of the Gas Companies shall keep upon their premises 
one or more properly closed vessels capable of containing from 
fifty to one hundred gallons of pentane, subject to any arrange¬ 
ment by which a Gas Company may obtain their supply of pentane 
which has been certified by the Gas Referees from another Gas 
Company. 

When a supply of pentane is needed for use in the testing 
places, a number of metal cans with screw stoppers, of a pattern 
approved by the Gas Referees, shall be provided sufficient to 
contain the whole quantity required. 

The Gas Referees shall then be informed by letter that this 
quantity of pentane awaits their examination; and they will 
arrange to attend at the premises where the pentane is stored. 
They will see the cans filled, and will affix a numbered lead seal 
to each can. 

They will then take away one or more of the cans for examina¬ 
tion ; the remaining cans must be kept until the Gas Referees 
have reported on the quality of the pentane. 

If the results of their testings are satisfactory, they will prepare 
as many labels as there are cans of pentane. Each label will 






25 6 


APPENDIX A. 


bear the embossed stamp of the Gas Referees, and will be 
numbered with the number or numbers impressed upon the lead 
seals on the cans. These labels will then be sent to the Company 
for attachment. 

No cans of pentane which the Gas Referees have certified 
are to be supplied to or used by any person or persons other 
than the Gas Examiners at the several testing places without the 
written permission of the Gas Referees, and a record must be 
kept by the Gas Company of the number of cans thus certified 
from time to time specifying the date, and the testing places to 
which they have been sent. If, however, application should be 
made to the Gas Referees by the London County Council, the 
Corporation of London, or any of the Metropolitan Gas Com¬ 
panies, to examine and certify pentane in reasonable quantities 
for non-official testings, they will be willing to do so. 

If the Gas Referees, after examination, find that the sample 
of pentane taken from any vessel does not satisfy the requirements 
of their notification, they will inform the Gas Company of the 
fact; and in such case the lead seals are to be cut off from the 
other cans filled from the same vessel, and returned to the Gas 
Referees. 

The Gas Companies will send the certified cans of pentane 
to the testing places in their several districts. The Gas Examiner 
at any testing place will take the presence of the Gas Referees’ 
lead seal and label, bearing identical numbers, upon any can, 
as evidence that the pentane therein has been certified, and no 
pentane shall be used in any testing that has not been so 
certified. 


APPENDIX D. 

The Table Photometer. 

The several parts of the apparatus stand upon a well-made 
and firm table, 5 feet 6 inches by 3 feet 6 inches, and 2 feet 
5 inches high. The upper surface of this table is smooth, level, 
and dead black. Upon this are placed or clamped in the posi¬ 
tions shown in Fig. 3 :— 

1. The Gas Meter. 

2. The Gas Governor. 

3. The Regulating Tap. 

4. The “ Metropolitan Argand Burner, No. 2,” and Sliding 

Base. 



THE TABLE PHOTOMETER. 


257 


5. The Flat Flame Burner and Sliding Base. 

6. The Slide, Connecting Rod and Photometric Scale, and 

Index. 



7. The Connecting Pipes. 

8. The Pentane Ten-Candle Lamp. 

9. The Photoped. 

10. The Aerorthometer. 

R 




















































258 


APPENDIX A. 


11. The Stop-Clock. 

12. Dark Screens; Mirrors; Measuring Rod; Small Block, 

and Pulley. 

1. The Gas Meter. 

The Gas Meter is sufficiently described on p. 250 of the 
Notification. 

2. The Gas Governor. 

The Gas Governor must be such as will effectually do away 
with any variation of pressure produced by the working of the 




Fig. 4.—The Regulating Tap. 


meter or other causes. A loose blackened screen, inches high 
by 6 inches wide, should be placed upon the base of the governor 
near the tank to prevent the water in the tank being heated by 
the flame of the gas burner. 

3. The Regulating Tap. 

This must have a large well-fitting conical plug with a round 
hole on each side of such a size as to allow gas to pass at the 































THE REGULATING TAP. 


259 


rate of about 4 cubic feet per hour under the pressure at the 
outlet of the governor. In addition there must be narrow saw- 
cuts on opposite sides of the two holes when viewed in plan, 
which will allow an additional passage of about 2 cubic feet of 
gas per hour when the tap is so turned that the holes and the 
saw-cuts are both opposite the orifices of the fixed part of the 
tap. The construction of the tap is shown in Fig. 4. The 



Fig. 5. 


index must be secured to the conical plug without any play, and 
its pointed end must pass over a scale graduated in degrees upon 
an arc of not less than 80 millimetres radius. The arc is to 
extend over 90°, and the degrees are to be numbered from o° 
to 90°. The arc is to be made of white enamel glass, and the 
divisions are to be etched upon it, and the marks filled in with 
black. The tap is to be off when the pointer is at one extremity 















































26 o 


APPENDIX A. 


of the arc at o°, and fully on when it is at the other extremity at 
90°. The small hole should be fully open at about 20° so that 
the action of the saw-cuts may extend over the remaining portion 
of the arc. 

The tap must be kept clean and sufficiently lubricated to 
work easily. 

4. The “ Metropolitan Argand Burner No. 2.” 

This is the burner described in Appendix E. It is to be 
mounted upon a tripod capable of moving upon the slides fixed 
to the table so that its distance from the photoped can be adjusted 
by means of the connecting rod. The construction of the cast- 
iron foot and slide is shown in Fig. 5. The height of the top of 
the cone is 353 millimetres above the table. The axis of the 
burner should be vertical. 


5. The Flat Flame Burner. 

The flat flame burner is Bray’s “No. 7 Economiser” fitted 
over a Bray’s “No. 4 Regulator.” 

The No. 7 Economiser is a slit burner, 
the width of the slit being .024 inch. 
The No. 4 Regulator is a union jet bur¬ 
ner. Both the economiser and burner 
contain gauze to steady the flow of gas. 

The burner is carried upon a sliding 
foot of the same construction as that 
used for the Metropolitan Argand Burner 
No. 2. An adapter is used to bring the 
height of the top of the burner to 353 
millimetres above the table, and the bur¬ 
ner is so turned that the plane of the 
flame makes an angle of about 45 0 with 
the line joining it and the slit in front of 
the photoped. When the Argand is being used the sliding foot 
carrying the flat flame burner may be made to stand out of the 
way as shown in Fig. 3. When the flat flame burner is being 
used the sliding foot carrying it is placed upon the slide and 
the Argand is pushed back as far as it will go, or if necessary it 
may be lifted off the slide. In either case the chimney should 
be removed so as not to reflect light upon the photoped. 



Fig. 6 . 


6. The Slide, Connecting Rod, and Photometric Scale. 

The slide fixed to the table on which the bases of the burners 
move constitutes with either of them a geometric slide, there being 

















CONNECTING PIPES. 


26 l 


the necessary five independent points of support. A rod of drawn 
brass, half an inch in diameter, is supported by three feet screwed 
to the table so that its under surface is one-eighth of an inch above 
the table. This rod is screwed down so as to be 50 millimetres to 
the left of the line, shown dotted in Fig. 3, which joins the gas 
burner with the slit in front of the photoped. Parallel with this, 
and at such a distance as to allow the wheel on the foot to run 
upon it, is screwed a piece of flat rolled brass, as shown. Exactly 
50 millimetres from the centre of the upright gas 
pipe, and in a direction at right angles to the line 
of motion, a hole, J inch in diameter, is made in 
the foot of each burner, into which a slightly 
tapered pin near one end of the connecting rod is 
to be placed, so that the burner may be pulled on 
the slide by the observer. This connecting rod is 
supported near the other end, as shown in Fig. 3, 
by a block, so placed that the rod is parallel with 
the dotted line already mentioned. The details of 
this block are shown in Fig. 6. The connecting 
rod has let into it at the observer’s end a strip of 
white enamel glass, on which is etched a photo¬ 
metric scale extending from 8 to 17 candles, and 
divided into tenths of a candle. A portion of this 
scale and the pattern to be followed is shown in 
Fig. 7. The index of the block is adjustable, so 
that when the Argand burner is placed at the 10 
candle distance by means of the measuring rod, as 
described under (12), the index may be clamped 
over the division 10. Then at all distances the 
number read upon the scale will accurately repre¬ 
sent the candle-power of the gas flame. 

7. The Connecting Pipes. 

These are to be made of half-inch (outside 
measure) composition piping except in the case of 
the two pipes which connect the three-way tap on Fig - 7 - 
the table with the two burners, where flexible 
metallic tube is to be used. They are to be connected with the 
different pieces of apparatus by f inch unions, except in the case 
of the gas meters, where the unions belonging to the meter may 
be retained. In all cases the boss of the union is to be attached 
to the apparatus and the cap and lining to the ends of the connect- 
ing pipe. These pipes are to be placed above the table. No 
grooves, recesses, or holes, other than the screw holes for the screws 
referred to in this Appendix, are to be made in the table. 

















262 


APPENDIX A. 


8. The Ten-Candle Pentane Lamp . 

This is described in Appendix A. 

The lamp is placed in position upon the table, the exact dis¬ 
tance of the steatite ring from the photoped being determined by 
means of the measuring rod as described under (12), p. 265. The 
swivel feet, which should fit loosely on the screws, shall then be 
clamped in position by the aid of the clamps shown in Fig. 8. 
The height of the top of the steatite burner is 353 millimetres 
above the table. 


9. The Photoped. 

The photoped is represented in Fig. 9; it consists of the follow¬ 
ing parts: a plate, 100 millimetres square, with a central hole, 21 
millimetres square. This is held in a vertical position by an up¬ 



right support so that the centre of the square is 400 millimetres 
above the table. The upright is carried , by a tripod with flat feet 
clamped to the table by clamps as shown in Fig. 9. To one face 
of the square plate is fastened, by two binding screws, a clamping 
plate, 60 x 40 millimetres, also with a central hole, 21 millimetres 
square, so that the two openings are opposite one another. A 
piece of suitable white paper is pinched between the two plates so 
as to cover the openings and project a little way below the clamp¬ 
ing plate. To the upper surface of the square plate is fixed a strip 
of glass, so that the lower edge is close to, and exactly parallel to, 
the plate, while the upper edge is so much in advance as will allow 
the reflection of the flames described on p. 267 to be observed. 
The clamping plate carries centrally a horizontal tube about 35 
millimetres in diameter and 30 in length. In this slides smoothly 
a smaller tube containing a diaphragm in which a rectangular slit, 
25 x 7 millimetres, has been cut. 








































THE AERORTHOMETER. 


263 


10. The Aerorthometer. 

The Aerorthometer is described and illustrated in Appendix F. 

In using the Aerorthometer, turn the screw up until the level 
of the mercury in the open tube is some distance below that of the 
mercury in the bulb tube; then turn the screw slowly down until 
the mercury stands at the same level in both tubes. The division 
at which the mercury now stands is the Aerorthometer reading. 



The Gas Examiner shall, not less often than once a month, 
compare the Aerorthometer reading with the reciprocal of the 
Tabular Number deduced from observations of Barometer and 
Thermometer, and if there is a difference of more than one-half 
per cent, the Aerorthometer is to be readjusted. If at any time 
the Aerorthometer is out of order the reciprocal of the tabular 
number is to be used. 


















































264 


APPENDIX A. 


11. The Stop-Clock. 

This is the clock ordinarily used in testing places, either attached 
to the meter or independent of it. It must be provided with 
mechanism for starting and stopping. It will facilitate the com¬ 
parison with the standard clock if it is made to give an audible 
sound, by means of a bell or otherwise, at the completion of each 
minute, and the number of minutes up to ten at least should be 
indicated by a separate hand. 

12. Dark Screens; Mirrors; Measuring Rod. 

Five dark screens are provided in order to prevent the inac¬ 
curacy and inconvenience to which stray light would give rise. 

The first is placed between the burners and the photoped in 
the position shown in Fig. 3. This screen is 500 millimetres wide 
and 400 millimetres high with its lower edge 100 millimetres above 
the table. It has two rectangular openings. The opening to the 
left is 40 millimetres wide and 55 high, and its lower edge is 350 
millimetres above the table. The opening to the right is 75 milli¬ 
metres wide, its lower edge is 340 millimetres above the table, 
and it extends to the top of the screen. The centre lines of these 
two openings are 300 millimetres apart. The screen is carried by 
two feet hinged to the table as shown in Fig. 3. Care must be 
taken that it is so placed that the whole of the flame under the tube 
c of the 10-candle lamp and the whole of the chimney and burner 
of the Argand or the whole of the flat flame can be seen through 
all parts of the slit in front of the photoped when the paper is 
removed for that purpose. 

The second dark screen consists of a piece of black velvet or 
black cloth 350 millimetres square stretched on a frame and sup¬ 
ported so that its lower edge is 150 millimetres above the table. In 
this is cut a hole 50 millimetres square with its lower edge 380 milli¬ 
metres above the table. This screen is placed close to the photoped 
but on the opposite side to that facing the lamps, and with the square 
hole opposite the square hole in the plate of the photoped. To 
the right side of the frame is hinged a light frame 350 millimetres 
high and 300 wide, with its lower edge 150 millimetres above the 
table. On this also is stretched black velvet or black cloth. This 
prevents the illuminated dial of the meter or arc of the regulating 
tap from interfering with the photometric observations, while at the 
same time it can be readily moved when these are to be observed. 

The third dark screen is about 500 millimetres wide and 570 
high. The fourth is about 450 wide and 570 high. These may 
be made of card painted dead black, or of thin wood, and may be 


DARK SCREENS ; MIRRORS ; MEASURING ROD. 265 


placed approximately in the positions shown in Fig. 3 and with 
their lower edges 180 millimetres above the table. In the fourth 
screen there is an opening about 150 millimetres square, fitted 
with glass of neutral tint, through which the height of the flame 
may be observed without fatiguing the eye. 

The fifth dark screen consists of a piece of black velvet or cloth 
large enough to form a black background to the lamps when viewed 
from the photoped. It is best placed upon the wall, but if that is 
inconvenient or other objects intervene, it should be supported on 
a stand, but always so as to be at least 300 millimetres behind the 
flames of the photometer. 

Three small mirrors are carried on light stands. One of these 
is made of ordinary flat silvered glass and is so placed as to enable 
the Gas Examiner, when seated at the photoped end of the table, 
on moving his head to the left of the second dark screen, to see 
by reflection the tip of the flame of the 10-candle lamp through 
the mica window in the tube c. 

The second, which should be about 120 millimetres in dia¬ 
meter, is convex, and should have a radius of curvature of about 
400 millimetres. It is placed on the observer’s right, and is so 
inclined that it casts a divergent beam of subdued light upon the 
divided arc of the regulating tap, upon the face of the meter, upon 
the aerorthometer, and upon the Gas Examiner’s note-book. 

The third, which is of flat glass, is placed on the top of the 
second screen, and is so arranged as to throw light on the photo¬ 
metric scale. 

All the apparatus on the table upon which light can fall and 
which might by reflection illuminate the photoped, or catch the 
eye of the operator, is to be painted dead black; or, if of finished 
brass, it is to be bronzed before being lacquered. 

The correct position of the photoped and of the burners is to 
be verified as follows :—A measuring rod has securely fastened to 
it transversely a cylindrical and shouldered plug which just fits into 
the steatite rings of the 10-candle lamp and of the Metropolitan 
Argand, there being a step on the plug to enable it to be used for 
either. The rod is balanced about and rests upon the burner. 
The rod is to be 1,000 millimetres from the axis of the plug to 
the extremity of the rounded ivory point. The rod must be 
capable of being placed in either burner without disarranging it, 
except in the removal of the glass chimney of the Metropolitan 
Argand or the conical shade of the 10-candle lamp. When the 
rod is in position upon either burner and the long end is moved 
gradually round toward the photoped, it should just come in 
contact with the paper under the clamping plate at the middle 
point. 


vUl 


266 


APPENDIX A, 

























































































THE METROPOLITAN ARGAND BURNER NO. 2 267 


When the burners have been lighted and the flames turned low, 
the reflection of one is to be observed over the other in the glass of 
the photoped. It should appear central; in that case the photoped 
is symmetrically placed with respect to the two burners. If the 
reflection does not appear central, the nut on the standard is to be 
loosened, and the plate turned until the reflection is central. The 
two lights are then to be turned up and the slit is to be moved in 
or out until the two rectangular spaces illuminated by the two lights 
just meet but do not overlap. 

A pattern Table Photometer is set up in the Gas Referees’ 
Office. This may be seen after permission in writing has been 
obtained from the Referees. 


APPENDIX E. 

The burner which has been adopted as the Standard Burner 
for testing gas was devised by Mr. Charles Carpenter, and has been 
called by him “The Metropolitan Argand Burner No. 2.” 

A full-sized drawing showing details is given in Fig. 10, on 
which also are marked the important dimensions. While these are 
given in every case to the nearest thousandth of an inch, this degree 
of accuracy is not essential. The important dimensions are those 
governing the gas and air passages, but all should be adhered to 
as nearly as workshop practice allows. 

The annular chamber from which the gas issues is made of 
steatite. 

The chimney to be used with this burner is 6 inches long and 
if- inch in internal diameter. 

Each testing place is provided with a box containing two wire 
gauges, one 0.058 inch, and the other 0.062 inch in diameter. 
The Gas Examiner must once in every month pass the smaller 
gauge through every hole in the burner, so as to clear out any loose 
obstruction or detect any hard concretion that might interfere with 
the proper discharge of the gas. He should at the same time 
satisfy himself that the larger gauge will not pass through the holes. 






268 


APPENDIX A. 










Fig. ii. 


















































































THE AERORTHOMETER. 


269 


APPENDIX F. 

The Aerorthometer. 

This is illustrated in Fig. 11. The mode of reading the instru¬ 
ment has been explained, p. 263 (10). A reading furnishes the 
figure required for correcting the volume of a gas measured over 
water at any ordinary temperature and pressure to that which the 
gas would have if measured over water under a pressure of 30 
inches of mercury and at a temperature of 6o° Fahr. Thus its 
reading corresponds to the figure derivable from a reading of the 
barometer and the thermometer and a reference to a table giving 
the tension of aqueous vapour at different temperatures. The in¬ 
strument consists of a bulb and vertical stem in which sufficient 
water is present to ensure that the air is saturated. The measur¬ 
ing tube, which terminates in a closed bulb, and a companion tube 
of the same calibre which is open to the air, dip into a reservoir of 
mercury in the base, the capacity of which can be adjusted by a 
regulating screw pressing on a leather cover. The relative volume 
of the bulb and tube down to any division is represented by the 
number belonging to that division. The capillary tube above the 
bulb is closed by a very small amount of sealing wax. In order to 
adjust the instrument the sealing wax is softened by heat and a 
small hole made through it. When the bulb has acquired the 
temperature of the air the regulating screw is to be turned until the 
two columns of mercury stand level at the calculated Aerortho¬ 
meter reading. Then the sealing wax stopping is again melted 
where it was perforated, by being touched from above with a heated 
wire while the base of the tube and the bulb are protected from 
heat by a wrapping of cotton wool. 


2JO 


APPENDIX A. 


APPENDIX G. 

TABULAR NUMBERS, being a Table to Facilitate the 

AT DIFFERENT TEMPERATURES AND UNDER 


Bar. 

Thermometer—Fahrenheit. 

40° 

42° 

44° 

46° 

-p*. 

00 

0 

50° 

52° 

54° 

56° 

58° 

6o° 

28.0 

•979 

•974 

•970 

.965 

.960 

.956 

• 95 1 

•946 

.942 

•937 

•932 

28.1 

•983 

.978 

•973 

.969 

•964 

•959 

•955 

.951 

•945 

.941 

.936 

28.2 

.986 

.981 

•9 77 

.972 

.967 

•963 

•958 

•953 

•949 

•944 

•939 

28.3 

.990 

. 9,85 

.980 

•976 

.971 

.966 

.961 

•957 

.952 

•947 

.942 

28.4 

•993 

.988 

•984 

•979 

•974 

• 97 o 

.965 

.960 

•955 

.951 

•946 

28.5 

•997 

.992 

•987 

•983 

.978 

•973 

.968 

.964 

•959 

•954 

•949 

28.6 

1.001 

•995 

.991 

.986 

.981 

•9 77 

.972 

.967 

.962 

•958 

•953 

28.7 

1.004 

•999 

•994 

•990 

.985 

.980 

•975 

•970 

.966 

.961 

.956 

28.8 

1.007 

1.003 

•998 

•993 

.988 

,984 

•979 

•974 

.969 

.964 

•959 

28.9 

1.011 

1.006 

1.001 

•997 

.992 

.987 

.982 

•977 

•9 73 

.968 

•963 

29.0 

1.014 

1.010 

1.005 

1.000 

•995 

•990 

.986 

.981 

•976 

.971 

.966 

29.1 

1.018 

1.013 

1.008 

1.004 

•999 

•994 

.989 

•984 

•979 

•975 

.969 

29.2 

1.021 

1.017 

1.012 

1.007 

1.002 

•997 

.992 

.988 

.982 

.978 

•973 

29-3 

1.025 

1.020 

1.015 

1.011 

1.006 

1.001 

.996 

.991 

.986 

.981 

.976 

29.4 

1.028 

1.024 

1.019 

1.014 

1.009 

1.004 

•999 

•995 

.990 

•985 

.980 

29-5 

1.032 

1.027 

1.022 

1.018 

1*013 

1.008 

1 -003 

•998 

•993 

.988 

•983 

29.6 

1.036 

1-031 

1.026 

1.021 

1.016 

1.011 

1.006 

1.001 

.996 

.992 

.986 

29.7 

1.039 

1.034 

1.029 

1.025 

1.019 

1.015 

I.OIO 

1.005 

1.000 

•995 

•990 

29.8 

1.043 

1.038 

1-033 

1.028 

1.023 

1.018 

1.013 

1.008 

1.003 

.998 

•993 

29.9 

1.046 

1.041 

1.036 

1.031 

1.026 

1.022 

1.017 

1.012 

1.007 

1.002 

•997 

30.0 

1.050 

1.045 

1.040 

1-035 

1.030 

1.025 

1.020 

1.015 

I.OIO 

1.005 

1.000 

30.1 

1-053 

1.048 

1.043 

1.038 

1-033 

1.029 

1.024 

1.019 

1.014 

1.009 

1.003 

30.2 

1.057 

1.052 

1.047 

1.042 

1.037 

1.032 

1.027 

1.022 

1.017 

1.012 

1.007 

30-3 

1.060 

1.055 

1.050 

1.045 

1.040 

1.036 

1.030 

1.025 

1.020 

1.015 

I.OIO 

30-4 

1.064 

1.059 

1.054 

1.049 

1.044 

1.039 

1.034 

1.029 

1.024 

1.019 

1.014 

30.5 

1.067 

1.062 

1.057 

1.052 

1.047 

1.042 

1.037 

1.032 

1.027 

1.022 

1.017 

30.6 

1.071 

1.066 

1.061 

1.056 

1.051 

1.046 

1.041 

1.036 

1-031 

1.026 

1.020 

30-7 

1.074 

1.069 

1.064 

1.059 

1.054 

1.049 

1.044 

1.039 

1.034 

1.029 

1.024 

30.8 

1.078 

1.073 

1.068 

1.063 

1.058 

1-053 

1.048 

1.043 

1.037 

1.032 

1.027 

30-9 

1.081 

1.076 

1.071 

1.066 

1.061 

1.056 

1.051 

1.046 

1.041 

1.036 

1.031 

31.0 

1.085 

1.080 

1.075 

1.070 

1.065 

1.060 

1.055 

1.049 

1.044 

1.039 

1.034 


*** The numbers in the above table have been calculated from the formula ?7 - U- 6 4 [h-a) , 


and a the tension of aqueous vapour at f. If v is any volume at t° and h inches 































TABULAR NUMBERS. 


271 


APPENDIX G. 


Correction of the Volume of Gas Measured over Water 

DIFFERENT ATMOSPHERIC PRESSURES. 





Thermometer- 

—Fahrenheit. 




62° 

64° 

66 ° 

0 

00 

VO 

7°° 

72 0 

1 

0 

76° 

00 

0 

8o° 

82° 

0 

00 

.927 

.922 

.917 

.912 

.907 

.902 

.897 

.892 

.887 

.881 

•875 

.870 

•930 

.926 

.921 

.916 

.911 

.905 

.900 

•895 

.890 

.884 

.879 

.873 

.934 

.929 

.924 

.919 

.914 

.909 

.904 

.898 

•893 

.887 

.882 

.876 

•937 

•932 

.928 

.922 

.917 

.912 

.907 

.902 

.896 

.891 

.885 

.880 

.941 

.936 

• 93 i 

.926 

.921 

.915 

.910 

.905 

.900 

.894 

.888 

.883 

•944 

•939 

•934 

.929 

•924 

.919 

.914 

.908 

•903 

.897 

.892 

.886 

•947 

•943 

•938 

•932 

.927 

.922 

.917 

.912 

.906 

.901 

•895 

.889 

.951 

.946 

.941 

•936 

• 93 i 

•925 

.920 

.915 

.909 

• 9°4 

.898 

•893 

•954 

•949 

•944 

•939 

•934 

•929 

.924 

.918 

• 9 i 3 

•9 °7 

.901 

.896 

.958 

•953 

•948 

•942 

•937 

•932 

•927 

.921 

.916 

.910 

.905 

•899 

.961 

.956 

.951 

.946 

.941 

•935 

•930 

•925 

.919 

.914 

.908 

•903 

.964 

•959 

•954 

•949 

•944 

•939 

•933 

.928 

•923 

• 9 i 7 

.911 

.906 

.968 

.963 

•958 

•952 

•947 

.942 

•937 

• 93 i 

.926 

.920 

.914 

.909 

.971 

.966 

.961 

.956 

.950 

•945 

.940 

•935 

•929 

•923 

.918 

.912 

•975 

.969 

.964 

•959 

•954 

•949 

•943 

•938 

.932 

•927 

.921 

.915 

.978 

•973 

.968 

.962 

•957 

•952 

•947 

.941 

•936 

•930 

•924 

.919 

.981 

.976 

.971 

.966 

.960 

•955 

.950 

•944 

•939 

•933 

.927 

.922 

.985 

.980 

•974 

.969 

.964 

•959 

•953 

•948 

•942 

•937 

• 93 i 

•925 

.988 

.983 

.978 

•972 

.967 

.962 

•957 

.951 

.946 

.940 

•934 

.928 

.991 

.986 

.981 

.976 

.970 

.965 

.960 

•954 

•949 

•943 

•937 

•932 

•995 

.990 

•985 

•979 

•974 

.968 

•963 

•958 

•952 

.946 

.941 

•935 

.998 

•993 

.988 

•983 

•9 77 

•972 

.966 

.961 

•955 

.950 

•944 

•938 

1.002 

.996 

.991 

.986 

.980 

•975 

.970 

.964 

•959 

•953 

•947 

.941 

1.005 

1.000 

•995 

•989 

•984 

.978 

•973 

.968 

.962 

.956 

.950 

•945 

1.008 

1.003 

•998 

•993 

.987 

.982 

.976 

.971 

.965 

•959 

•954 

.948 

1.012 

1.006 

1.001 

.996 

.990 

•985 

.980 

•974 

.969 

•963 

•957 

.951 

1.015 

I.OIO 

1.005 

•999 

•994 

.988 

•983 

•977 

•972 

.966 

.960 

•954 

1.018 

1.013 

1.008 

1.003 

•997 

•992 

.986 

.981 

•975 

.969 

•963 

•957 

1.022 

1.017 

I.OI 1 

1.006 

1.000 

•995 

.990 

.984 

.978 

•972 

.96 7 

.961 

1.025. 

1 020 

1.015 

1.009 

1.004 

•998 

•993 

.987 

.982 

.976 

.970 

.964 

1.029 

1.023 

1.018 

1.013 

1.007 

1.002 

.996 

.991 

.985 

•979 

•973 

.96 7 


where h is the height of the barometer in inches, t the temperature on the Fahrenheit scale, 


pressure and V the corresponding volume at 6o° and 30 inches pressure, V = z> n . 








































2J2 


APPENDIX A. 


APPENDIX H. 

Test for Sulphuretted Hydrogen. 

The apparatus represented by Fig. 12 consists of a plate with 
a circular channel half filled with mercury in which rests a bell- 
glass, held down in position by an arm and cap not shown in 
the figure. A central tube connected below with the gas inlet rises 
nearly to the top of the bell-glass, and carries midway wires pointed 
and curved at the end, from each of which a slip of lead paper 
hangs. 

A second pipe passing through the plate and terminating above 



in a short elbow provides an outlet for the gas, which is burnt as 
it issues from a governor-burner passing gas at about the rate of 
five cubic feet per hour. 


APPENDIX K. 

Sulphur Test. 

The apparatus to be employed is represented by Fig. 13, and 
is of the following description The gas is burnt in a small Bun¬ 
sen burner with a steatite top, which is mounted on a short cylin¬ 
drical stand, perforated with holes for the admission of air, and 












































SULPHUR TEST. 


273 


having on its upper surface, which is also perforated, a deep cir¬ 
cular channel to receive the wide end of a glass trumpet-tube. 
There are both in the side and in the top of this stand fourteen 
holes of 5 millimetres in diameter, or an equivalent air-way. 
On the top of the stand, between the narrow stem of the burner 
and the surrounding glass trumpet-tube, are to be placed pieces of 
commercial sesqui-carbonate of ammonia weighing in all about 2 
ounces. 

The products both of the combustion of the gas and of the 
gradual volatilisation of the ammonia salt go upwards through the 
trumpet-tube into a vertical glass cylinder with a tubulure near 
the bottom, and drawn in at a point 
above this to about half its diameter. 

From the contracted part to the top 
the cylinder is packed with balls of 
glass about 15 millimetres in diameter, 
to break up the current and promote 
condensation. From the top of this 
condenser there proceeds a long glass 
pipe or chimney slightly bent over at 
the upper end, serving to effect some 
further condensation, as well as to 
regulate the draught and afford an exit 
for the uncondensable gases. In the 
bottom of the condenser is fixed a 
small glass tube, through which the 
liquid formed during the testing drops 
into a flask placed beneath. 

The following cautions are to be 
observed in selecting and setting up 
the apparatus:— 

See that the inlet pipe fits gas-tight Fig. 13. 

into the burner, and that the holes in 

the circular stand are clear. If the burner gives a luminous 
flame, remove the top piece, and having hammered down 
gently the nozzle of soft metal, perforate it afresh, making as small 
a hole as will give passage to two-thirds of a cubic foot of gas per 
hour at a convenient pressure. 

See that the tubulure of the condenser has an internal diameter 
of not less than 18 millimetres, and that its outside is smooth and 
of the same size as the small end of the trumpet-tube; also that 
the internal diameter of the contracted part is not less than 30 
millimetres. 

See that the short piece of indiarubber pipe fits tightly both to 
the trumpet-tube and to the tubulure of the condenser. 

S 
















APPENDIX A. 


274 

The small tube at the bottom of the condenser should have its 
lower end contracted, so that when in use it may be closed by a 
drop of water. 

The indiarubber pipe at the lower end of the chimney-tube 
should fit into or over, and not simply rest upon, the mouth of the 
condenser. 

A central hole, about 50 millimetres in diameter, may with 
advantage be made in the shelf of the stand. If a beaker is kept 
on the table below, the liquid will still be preserved if by any 
accident the flask is not in its place. 


APPENDIX L. 

The Gas Calorimeter. 

The Gas Calorimeter, which has been designed by Mr Boys, 
is shown in vertical section in Fig. 14. It consists of three parts, 
which may be separated, or which, if in position, may be turned 
relatively to one another about their common axis. The parts are 
(1) the base a, carrying a pair of burners b, and a regulating tap. 
The upper surface of the base is covered with a bright metal plate 
held in place by three centering and lifting blocks c. The blocks 
are so placed as to carry (2) the vessel d which is provided with 
a central copper chimney e and a condensed water outlet f. 
Resting upon the rim of the vessel d are (3) the water circulating 
system of the calorimeter attached to the lid g. Beginning at the 
centre where the outflow is situated there is a brass box which acts 
as a temperature equalising chamber for the outlet water. Two 
dished plates of thin brass k k are held in place by three scrolls 
of thin brass lll. These are simply strips bent round like 
unwound clock springs, so as to guide the water in a spiral direc¬ 
tion inwards, then outwards and then inwards again to the outlet. 
The lower or pendent portion of this box is kept cool by circulat¬ 
ing water, the channel for which may be made in the solid metal, 
as shown, on the right side, or by sweating on a tube as shown on 
the left. Connected to the water channel at the lowest point by 
a union are five or six turns of copper pipe such as is used in a 
motor car radiator of the kind known as Clarkson’s. In this a 
helix of copper wire threaded with copper wire is wound round the 
tube, and the whole is sweated together by immersion in a bath of 
melted solder. A second coil of pipe of similar construction sur¬ 
rounding the first is fastened to it at the lower end by a union. 
This terminates at the upper end in a block, to which the inlet 
water box and thermometer holder are secured by a union as shown 



THE GAS CALORIMETER. 


275 


at o. An outlet water box p and thermometer holder are simi¬ 
larly secured above the equalising chamber h. The lowest turns 




of the two coils m<n are immersed in the water which in the first 
instance is put into the vessel D. 



































































APPENDIX A. 


276 

Between the outer and inner coils mn is placed a brattice. Q 
made of thin sheet brass, containing cork dust to act as a heat in¬ 
sulator. The upper annular space in the brattice is closed by a 
wooden ring, and that end is immersed in melted rosin and bees¬ 
wax cement to protect it from any moisture which might condense 
upon it. The brattice is carried by an internal flange which rests 
upon the lower edge of the casting h. A cylindrical wall of thin 
sheet brass, a very little smaller than the vessel d, is secured to 
the lid so that when the instrument is lifted out of the vessel and 
placed upon the table the coils are protected from injury. The 
narrow air space between this and the 
vessel d also serves to prevent inter¬ 
change of heat between the calori¬ 
meter and the air of the room. 

The two thermometers for reading 
the water temperatures and a third for 
reading the temperature of the outlet 
air are all near together and at the 
same level. The lid may be turned 
round into any position relatively to 
the gas inlet and condensed water 
drip that may be convenient for ob¬ 
servation, and the inlet and outlet 
water boxes may themselves be turned 
so that their branch tubes point in any 
direction. 

A regular supply of water is main¬ 
tained by connecting one of the two 
outer pipes of the overflow funnel 
shown in Fig. 15 to a small tap over 
the sink. The overflow funnel is 
fastened to the wall about 1 metre 
above the sink and the other outer 
pipe is connected to a tube in which 
there is a diaphragm with a hole about 2.3 mm. in diameter. 
This tube is connected to the inlet pipe of the calorimeter. 
A piece of stiff rubber pipe long enough to carry the outflow 
water clear of the calorimeter is slipped on to the outflow 
branch and the water is turned on so that a little escapes 
by the middle pipe of the overflow funnel, and is led by a third 
piece of tube into the sink. The amount of water that passes 
through the calorimeter in four minutes should be sufficient to fill 
the graduated vessel shown in Fig. 16 to some point above the 
lowest division, but insufficient in five minutes to come above the 
highest division. If this is not found to be the case, a moderate 


/ 0 

0 * \ 

1 

h , 

" 1 ! 

1 b J|'i, 

M | j 
i'll 

m 

m 

\ 0 

0I 

Voy 


Fig. 15. 


















THE GAS CALORIMETER. 


277 


lowering of the overflow funnel or reaming out of the hole in the 
diaphragm will make it so. The overflow funnel should be pro¬ 
vided with a lid to keep out dust. 

The thermometers for 
. reading the temperature of 
the inlet and outlet water 
should be divided on the 
Centigrade scale into tenths 
of a degree, and they should 
be provided with reading 
lenses and pointers, such as 
are shown in Fig. 17, that 
will slide upon them. The 
thermometers are held in 
place by corks fitting the 
inlet and outlet water boxes. 

The positions of these ther¬ 
mometers should be inter¬ 
changed every month. The 
thermometers for reading the 
temperature of the air near the 
instrument and of the effluent 
gas should be divided on the 
Centigrade scale into degrees. 

The flow of air to the 
burners is determined by 
the degree to which the 
passage is restricted at the 
inlet and at the outlet. The 
blocks c which determine 
the restriction at the inlet 
are made of metal x 3 g inch 
or about 5 millimetres thick, 
while the holes round the lid 
which determine the restric¬ 
tion at the outlet are five in 
number and are 
16 millimetres in 
The thermometer used for 
finding the temperature of 
the effluent gas is held by a 
cork in the sixth hole in the 

lid so that the bulb is just above the upper coil of pipe. 

The calorimeter should stand on a table by the side of a sink 
so that the condensed water and hot-water outlets overhang and 


or 


-§ inch 
diameter. 



JndroL 1 £ 5 Ll-t 


■iLha- 




Mauwem s. 


Fig. 16. 








































278 


APPENDIX A. 




deliver into the sink. 
A suitable change¬ 
over funnel is shown 
in Fig. 18. A piece 
of indiarubber tube 
reaching nearly to the 
base should be at¬ 
tached to the waste 
waterpipe so as to 
avoid splashing, and 
another piece may 
conveniently be 
slipped on to the 
condensed water out¬ 
let so as to lead the 
condensed water into 
a flask, but care 


should betaken 
that the small 
side hole is not 
covered by the 
tube. A glass 
vessel must be 
provided of the 
size of the ves¬ 
sel D contain¬ 
ing water in 
which is dis¬ 
solved suffi¬ 
cient carbonate 
of soda to make 
it definitely al¬ 
kaline. The ca¬ 
lorimeter after 
use is to be 
lifted out of its 
vessel d and 
placed in the 
alkaline solu¬ 
tion and there 
left until it is 
again required 
for use. The 
liquid should 
not, when the 



Lt4ttttL 1 Li Li Lai LT~lao pi 1 


Fig. 18. 

















































































CALORIFIC POWER OF GAS. 


279 


calorimeter is placed in it, come within 2 inches of the top of the 
vessel. The liquid must be replenished from time to time, and 
its alkalinity must be maintained. 


CALORIFIC POWER OF GAS. 


Form with Example of Calculation (see p. 249). 


Water. 

Inlet. Outlet. 

3 - 45 ° C. 33.22 0 C. 
•23 

^3 

‘23 

8.4.6 .21 


Air. 

Inlet. Outlet. Time by Stop-Clock. 

13 0 C. 12 0 C. 4 min. 2 sec .=242 sec. 

One-sixth difference —0.3. 


Barometer, 2Q.g inches ...\ 
Meter thermometer, 60° F./ 


Tabular Number — 


997 - 


8.46 


‘23 

.23 Water collected, 2.080 litres. 

.23 Condensed water in 20 min. = 1,200 sec., 40.3 c.c. 


‘23 


8.47 

.24 

Log. 

24.77 = 

7 -3939 

8.46 

.24 

Log. 

3 

A 771 


.24 

Log. 

2.080 — 

3181 


5 ) 3 - 4 1 



2.18QT 


3) -682 

Log. 

-997 = 

1.9987 


33‘ 2 3 

Log. 

155-0 

2. i go4 


8.46 


Subtract 0.3 


24.77 

154-5 

= Gross Calorific Power. 

Log. 

Log. 

II H 

0 

1.603 

2.384 

Log. 1200 
Log. .gg7 

= 3-079 
= 7 -999 

Log. 

1.86 = 

.270 


3.078 

Gross 134.3 

Log. 13.2 = 

4‘ 2 39 

3.078 

1.181 




I 39‘3 


Net Calorific Power. 



















280 


APPENDIX A. 


APPENDIX M. 

The Gas Referees’ Street Lamp Pressure Gauge. 


This 
any hou 


instrument is for the purpose of testing in any street at 
r the pressure at which gas is supplied. Its construction 
and mode of use are as follows :— 
Within a lantern, provided with a 
handle for carrying and feet for resting 
on the ground, is placed a candle-lamp, 
to give light for reading the gauge. In 
front of the candle-lamp is a sheet of 
opal glass, and in front of this a glass 
U tube, partly filled with coloured 
water, and communicating at one end 
with the air, at the other with a metal 
pipe, which passes through the bottom 
of the lantern. In order to read easily 
and accurately the difference of level 
of the liquid in the two limbs, a scale 
divided into tenths of an inch is made 
to slide between them with sufficient 
friction to retain it in any position. 
The zero of the scale having been 
brought level with the surface of the 
liquid which is exposed to the gas, 
the height above this of the surface 
which is exposed to the air can be read 
directly. The lantern is closed in 

front by a glass door, at each side of 
which is a reflector for throwing light 
upon the scale of the gauge. Above 
each limb of the U tube is a tap which 
can be closed when the instrument is 
not in use, to prevent the liquid being 
accidentally spilt. 

To make a testing of pressure the 
governor and burner of a street lamp 
are to be removed, and the pressure 
gauge is to be screwed on to the gas- 
pipe, by which it is supported. In 
places where incandescent burners are 
used, the L-shaped pipe described on 
p. 249 is to be used for the attachment 
of the pressure gauge. The cock is 
Fig. 19. then turned on, and a reading made. 
































ONE-TWELFTH OF A CUBIC FOOT MEASURE. 281 


If on turning off the cock the level of the liquid is unchanged, or 
changes slowly, the reading is correct; but if the level changes 
quickly, the junction between the lamp and the gauge must be 
made more perfect, and the testing repeated. A small leakage 
is immaterial, provided the cock is turned fully on. 

The pressure at the top of a lamp column is greater by about 
0.1 inch than that at the main, which is the pressure required. 
Accordingly a deduction of o. 1 inch from the observed pressure is 
to be made. 


APPENDIX N. 

The Gas Referees’ One-Twelfth of a Cubic Foot 
Measure. 

This instrument, which was designed by Mr Harcourt, is 
represented in Fig. 20; it consists of a vessel of blown glass of a 
cylindrical form with rounded ends terminating in short tubes about 
40 millimetres in diameter outside, which tubes are reduced at 
their outer ends to about 20 millimetres in diameter outside. Lines 
are etched round each tubular neck in such positions that the capa¬ 
city of that portion of the vessel included between these marks is 
exactly one-twelfth of a cubic foot when the glass is at the ordinary 
temperature. No correction is needed for the cubical expansion 
of the glass. The two tubular necks of the instrument pass through 
two boards placed below and parallel to the top of a small four¬ 
legged table. For convenience the upper one of these two boards 
is made in two parts and hinged to the legs. 

Into each end of the instrument a glass tube about 8 millimetres 
in diameter outside is fitted gas and water-tight by means of india- 
rubber corks, in such positions that the inner end of the upper 
tube lies exactly in the plane of the mark at its end of the instru¬ 
ment, while that of the lower is about 1 mm. below the mark. 

The upper tube terminates in a T, each branch of which is 
provided with a stop cock. 

A separate stand carries two shelves, the upper one about 40 
millimetres below the level of the upper mark and the lower one 
below the level of the lower mark. The lower shelf is adjustable, 
and must be so placed that the action about to be described shall 
take place. 

A water vessel is provided having a capacity of about one-tenth 
of a cubic foot. It should be made of brass or copper, tinned on 
the inside. It has a tubulure near the bottom, to which is fitted a 
metal tap. The end of the tap is to be turned slightly downwards, 



282 


APPENDIX A. 


and is to have a diameter outside of about 8 millimetres. The 
size of the way through the tap and of the connections is such that 
when a meter is being proved in the manner to be described, the 
water fills the instrument from one mark to the other in about one 
minute. The water vessel has a tubulure above for filling it, closed 
by a cork through which passes a narrow glass tube, so that 



Fig. 20. 


air may enter or escape. The end of the tube is bent round upon 
itself in the form of a crook, so as to exclude dust and dirt. An 
indiarubber tube connects the tube at the base of the measure 
with the stop-cock of the water vessel. An ordinary chemical 
thermometer is provided for taking the temperature of the water. 

The pipe supplying gas to each meter is provided near the 


























































ONE-TWELFTH OF A CUBIC FOOT MEASURE. 283 

meter with a three-way stop-cock carrying a short branch pipe, so 
formed that it either connects the gas supply only with the 
branch pipe, the meter only with the branch pipe, or the gas 
supply with the meter, in which latter case the branch pipe is cut 
off from both. The index of the tap shows which communi¬ 
cation is open. The branch pipe is so shaped as to he convenient 
for the attachment of an indiarubber tube. 

In order to put the instrument in adjustment the water vessel 
is placed upon the upper shelf, and water is poured into it until the 
water has risen about one-quarter of an inch in the upper narrow 
tube of the glass measure. One branch of the glass T is then 
connected by an indiarubber pipe with the branch of the three-way 
stop-cock. This is now turned so as to connect the branch pipe 
with the gas supply. 'The stop-cock in the branch of the glass T 
to which the rubber tube is attached is turned on, and the water 
vessel is placed on the lower self. The water will run back into 
the vessel. The flow should cease when the water has just begun 
to descend in the lower tube ; if not, the height of the lower shelf 
must be adjusted until this is the case. 

The space above the upper mark is always filled with gas, and 
that below the lower mark with water, so that the capacity of these 
portions of the instrument has no effect upon the measurements. 
The narrow tubes are so small that a variation of even an inch of 
the level at which the water stands in them has no appreciable 
effect upon the meter reading. 

The apparatus shall only be used in proving a meter when the 
temperature of the meter and of the water in the water vessel have 
been found not to differ by more than two degrees Fahrenheit. 

In order to prove the meters used in the various testings, the 
position of the index is taken when the instrument has been put in 
adjustment and filled with gas as described. The tap of the water 
vessel is turned off; the three-way tap is turned half-way towards 
the position which will connect the instrument with the gas-meter, 
and the pressure of the gas in the instrument is reduced to atmo¬ 
spheric pressure by momentarily opening the tap in the free branch 
of the glass T. The water vessel is placed upon the upper shelf, 
the regulating tap (Fig. 4) is turned on, the three-way tap is turned 
into such a position as will connect the instrument with the meter, 
and the tap of the water vessel is turned on. One-twelfth of a 
cubic foot of gas will then be discharged through the meter. Fig. 
20 represents this operation in progress. The three-way stop-cock 
is then turned so as to fill the instrument with gas, the water vessel 
is placed upon the lower shelf, the gas is reduced to atmospheric 
pressure as before, and a second, and again a third quantity is 
discharged through the meter. Should the hand attached to the 


284 


APPENDIX A. 


axle of the measuring drum have travelled in the three revolutions 
as much as one division beyond the point from which it started, 
some water must be removed from the meter; if the travel of the 
meter hand is as much as one division short of this point, some 
water must be poured in. The operation is then to be repeated 
until the error is found to fall within the specified limits. 


APPENDIX O. 

“Each Gas Examiner shall on each day make and deliver a 
report of the result of the testings of the gas supplied by the 
Company conducted by him on the immediately preceding day to 
the controlling authority, to the Gas Referees, to the Chief Gas 
Examiner, and to the Company, and the books kept by a Gas 
Examiner for recording the results of the testing of such gas by 
him shall be open at all reasonable times to the inspection of 
the Company without payment.” (Gas Light and Coke and other 
Gas Companies Acts Amendment Act, 1880, Section n.) 

“Each Gas Examiner shall forthwith deliver to the controlling 
authority, to the Gas Referees, to the Chief Gas Examiner, and to 
the Company a report of the result of each testing conducted by 
him under the provisions of this section.” (London Gas Act, 
1905, Section 5 (2).) 

In making his returns for Illuminating Power as given by the 
flat flame, and for Calorific Power, the Gas Examiner shall put 
down the result of each testing, and the time at which the testing 
was made. 

On p. 286 is an example of the form in which returns are 
to be made. 


ILLUMINATING POWER OF GAS. 



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County of London Gas-Testing Place , i Carlyle Square , Chelsea , S.W. 


286 


APPENDIX A. 


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LOAN APPARATUS. 


287 


APPENDIX P. 

Loan Apparatus. 

In order to make the suspension of any of the operations of 
gas testing, which occur from time to time owing to a defect in 
some piece of apparatus, as short as possible, the Gas Referees 
keep at their office one or two of each of the pieces of apparatus 
likely to need replacement. 

On receiving an application from any Gas Examiner, or from 
the Chemist to the London County Council, or from the City Gas 
Examiner, or from the Gas Company, for the temporary loan of a 
piece of apparatus to take the place of similar apparatus at one of 
the testing places which needs to be sent away for repair or replaced 
by new apparatus, the Gas Referees will state whether they have 
such apparatus in stock, and if so when they will be able to deliver 
it to the messenger sent to convey it to the testing place. 


APPENDIX B. 


Cyanogen in Purifying Materials and the 
Influence of Ammonia upon its Formation 
in Purification. 

By Dr Burschell, Carlsruhe ( Journ . des Usines a Gaz , 1893). 

The formation of Prussian blue during gas purification is an 
important matter; researches by Leybold show that it is formed 
during revivification of the material, the cyanides of iron formed 
in the purifiers being transformed by oxidation into Prussian blue. 
It is uncertain whether a cyanide of iron is formed, but it may be 
assumed that Prussian blue is not formed in the first purifiers 
because it cannot exist in presence of a large excess of sulphuretted 
hydrogen. 

The absorption of cyanogen in the purifiers is also not due to 
a double decomposition between the hydrocyanic acid or the 
cyanide of ammonium and the sulphate of iron, because purifying 
material which has not taken up sulphuretted hydrogen does not 
take up cyanogen, or only in a very slight degree. Old material, 
on the contrary, readily absorbs cyanogen, but it frequently con¬ 
tains sulphocyanogen in the presence of ammonia, which renders 
it almost useless. 

Experiments made by the author prove that cyanogen is taken 
up in the presence, as well as in the absence, of ammonia. 

Ferrocyanogen may be converted into sulphocyanogen, or the 
reverse, but while ferrocyanogen is easily convertible it is very 
difficult to effect the contrary conversion. 

The presence of ammonia during the purification of gas influ¬ 
ences the formation of cyanogen in two ways, and although it may 
be difficult to avoid ammonia in the purifiers, the formation of 
sulphocyanogen during revivification may be minimised by avoid¬ 
ing excessive heating, and by removing the ammonia as quickly 



COMPOSITION AND ANALYSIS OF WATER-GAS. 289 

as possible by spreading it out in thin layers, &c., when removed 
from purifiers. 

The transformation of cyanogen into sulphocyanogen takes 
place readily in the presence of ammonia and sulphuretted 
hydrogen. Sulphocyanogen compounds are formed as well as 
other cyanogen compounds. 

A small portion is arrested in the first purifiers, where the 
ammonia and sulphuretted hydrogen are taken up in large 
quantities; the cyanogen then attacks other portions of the puri¬ 
fying material in which there is no sulphuretted hydrogen and 
only traces of ammonia, which, on account of the oxide of iron 
present, favours the formation of ferrocyanides, and these portions 
of the cyanogen may, by a suitable treatment of the purifying 
material, be utilised for the production of Prussian blue. 


The Chemical Composition and Technical 
Analysis of Water-Gas. 

By Edward H. Earnshaw (The American Gas Light Journal , 
lxix., 1898). 

The oils used in producing carburetted water-gas are decom¬ 
posed in the fixing chamber with production of hydrogen, gaseous 
hydrocarbons, naphthalene, benzene, and its homologues. 

The constituents of coal-gas and carburetted water-gas are the 
same, but their proportions vary. The following Table shows the 
representative analyses:— 


Constituents. 


Coal-Gas. 



Benzene vapour 
*Heavy hydrocarbons 
Carbonic oxide 
Hydrogen 
Marsh gas 
Higher paraffins 
Carbonic acid 
Oxygen 
Nitrogen 


Per Cent. Per Cent. 

O.50 0.60 

4.25 12.80 

8.04 30.70 

47-04 32-40 

36.02 13-90 

0.00 2.40 

1.60 2.70 

0.39 0.70 

2.16 3.80 


100.00 


100.00 


The heavy hydrocarbons consist chiefly of ethylene and its homologues. 





290 


APPENDIX B. 


Estimation of Ferrocyanide in Spent Oxide. 

By E. Donath and B. Moyosches (Zeits. fiir Angew. Chem ., 
1899, PP. 345 - 347 )- 

50 grams of the powdered material (or the residue after the 
sulphur has been extracted) are taken, placed in a litre flask, and 
100 to 150 c.c. of 15 per cent, solution of caustic potash added, 
and heated on a sand bath, with vigorous shakings, for some 
time. The volume is then made up to 1,030 c.c. with distilled 
water (the residue from 50 grams occupies a volume equal to 
30 c.c., and the liquid is equal to 1,000 c.c. net). It is then 
filtered off, and an aliquot part of the filtrate utilised for 
estimation. 80 grams of sodium hydroxide are dissolved in 
water and made up to 1 litre and thoroughly well agitated, 
20 c.c. bromine then added, and well mixed. This oxidising 
agent can be added to filtrate to be tested as required. The 
mixture is then boiled until gas is given off, and a brick-red 
precipitate is thrown down. The precipitate is filtered off and 
afterwards dissolved in hydrochloric acid, and the proportion 
of iron determined by permanganate test. The amount of iron x 
7.5476 gives the equivalent of potassium ferrocyanide, K 4 ,FeCy 6 , 
and this multiplied by .687 gives the Prussian blue. 


Prussian Blue in Spent Oxide by Feld’s Method. 

R. Witzeck (Journ. Soc. Chem. Ind., vol. xxiii., p. 13, extracted 
from Journ. fur Gasbeleuchtung). 

The total cyanogen is determined by pulverising in a mortar 

2 grams of spent oxide (0.5 gram of mud) with 1 c.c. of — 

1 

ferrous sulphate solution, and 5 c.c. of 8N sodium hydrate solu¬ 
tion for five minutes ; 30 c.c. of 3N magnesium chloride solution 
are added, drop by drop, with continuous stirring, the contents 
being washed into a distillation flask of about 700 c.c. capacity, 
and the washing, &c., made up to about 200 c.c. After a few 

minutes’ boiling, 100 c.c. of boiling — mercuric chloride solution 

10 

are added to the boiling liquid, and the mixture boiled for ten 
minutes, all the cyanogen being thus converted into mercuric 
cyanide. 


ANALYSIS OF MONAZITE SANDS. 


291 


The flask is now attached to a condenser leading into a 
receiver, the latter being connected to a safety-bulb tube; 30 c.c. 
of 4N sulphuric acid are added and the liquid is distilled for 
about thirty minutes, the products passing over into the receiver 
and bulb, which contain 20 c.c. of 2N sodium hydrate. Some¬ 
times the distillate is turbid owing to presence of sulphur, if so, 
an excess of lead carbonate is added, agitate and filter, and an 
aliquot portion taken for titration. This is performed by adding 

N 

5 c.c. of 4N potassium iodide solution, and then titrate with — 
silver nitrate solution until a yellow turbidity appears. 

1 c.c. of — silver nitrate = .009556 gram of Prussian blue. 


Monazite Sands. 

Dr C. Richard Bohm (Journal of Gas Lighting, , vol. xciii., 

P- 43 °)- 

The average analysis of four samples by Hussak and Reitniger 
of a monazite from Bandeira de Mello are given under I., and of 
a sample from Bandeirenha in Minas-Geraes, II. 



I. 

II. 


Per cent. 

Per cent. 

p 2 o 5 

25.51 

29.18 

Ce 2 0 3 

32.I4 

32.46 

Nd 2 O g - 

I5-38 

l6.8l 

(LaPr) 2 0 3 - 

10.61 

19.21 

Th0 2 

IO.05 

I.09 

Fe 2 0 3 

1.79 

O.61 

CaO 

0.20 

O. IO 

Zr0 3 

0.60 


A1 2 0 3 

O.84 


Si0 3 

2.63 


h 2 o 

O.92 



IOO.67 

99.46 


Humidity, Effect of, on the Pentane Lamp. 
(Journal of Gas Lighting , vol. xciii., p. 162.) 

This subject was dealt with in the Report of the Research 
Committee of the American Gas-Light Association, by Mr J. B. 
Klump. 



292 


APPENDIX B. 


The object was to present a means of comparing photometric 
standards or other lights represented by open flame burners, with 
vacuum electric standards or such lights as are not affected by 
varying atmospheric conditions. Attention was drawn to the 
work on the same subject by Dr Liebenthal of Berlin in 1895, 
and by C. C. Paterson of the National Physical Laboratory in 
1904. 

These show that the standard light is affected by the presence 
of carbonic acid, barometric pressure, and moisture. For com¬ 
mercial purposes the variation due to carbonic acid may be 
omitted. 

With regard to barometric pressure Dr Liebenthal has shown 
that 25 mm. of mercury affected the Hefner lamp 0.28 per cent., 
and the 1 candle pentane lamp 1.2 per cent. 

Mr Paterson’s readings under a maximum variation of the 
barometer from 739 to 780 mm. show a variation of lamp value 
of less than 1.6 per cent, from the normal. The effect of 
moisture is shown to be considerable. A variation of 1 per cent, 
in candle-power for each 1.515 litre of water vapour per cubic 
metre of dry air is obtained. He states that with a temperature 
of 70 degrees Fahr. and a humidity of 60 per cent., the variation 
will be 3.3 per cent., i.e., the actual light-giving value of the 10- 
candle pentane lamp will be 9.67 candles. 

To show the necessity of making corrections, the author gives 
a Table of the average humidity for Philadelphia for the past 
thirty-four years, from which it is seen that the moisture varies 
from 4.2 to 20.2 litres per cubic metre, and the percentage varia¬ 
tion in candle-power ranges from +3.4 to -7.2. 


Estimation of Carbon Bisulphide in Benzene. 


By D. Starovinus (Journ. Gasbeleuchtung, p. 8). 


25 c.c. of the sample are mixed with 70 c.c. of 96 per cent, 
alcohol, and 10 c.c. 2N sodium hydroxide. After half an hour 
5 c.c. of concentrated hydrogen peroxide are added, the alcohol 
evaporated off, and the sulphate formed precipitated by barium 
chloride, and estimated as usual. 

The method can also be used volumetrically by using 10 c.c. 

of normal alkali, and titrating the excess with — acid, using 

methyl orange as indicator. 


1 c.c. of — 
5 


alkali = 0.019 gram of carbon bisulphide. 


CS 2 AND S IN BENZENE. 


293 


Estimation of CS 2 and S in Commercial Benzene. 

By Ed. S. Johnson (Journ. Amer. Chem. Soc ., p. 1209). 

CS 2 .—This is converted into potass xanthate by saturated 
alcoholic potassium hydrate, and is removed from the benzene by 
repeated washings with alkaline water. The xanthate is then 
converted into the copper compound by slightly acidifying with 
acetic acid, and precipitating with copper sulphate. The precipi¬ 
tate is filtered, washed, and ignited to oxide. 

One part of oxide = 1.75 of carbon disulphide. 

Total Sulphur .—.5 c.c. of the sample are vaporised by a 
current of hydrogen, they are then burnt in a special apparatus in 
oxygen, and the products of combustion are absorbed in bottles 
containing sodium carbonate and bromine solution. This 
causes a complete conversion of the sulphur into sulphuric acid, 
which may either be estimated gravimetrically or volumetrically 
by collecting the products of combustion in a standard solution of 
sodium hydrate, and, after adding some neutral hydrogen per¬ 
oxide, the excess of alkali is titrated back with standard acid. 


Test for CN in Presence of HCN. 

By Theodor Wallis (Journal Chem . Soc., from “ Annalen,” 

pp- 353-362)- 

The method for the detection of cyanogen in the presence of 
hydrogen cyanide:—The mixture is passed into an acidified solu¬ 
tion of a silver salt, the silver cyanide removed, the silver in the 
solution precipitated by yellow ammonium sulphide, a few drops 
of alkali are added, and after filtration and evaporation the 
test for thiocyanate is applied. The estimation of cyanogen 
and hydrogen cyanide is effected by passing the mixture into a 
solution of sodium hydroxide, the HCN and one-half of the CN 
is estimated as silver cyanide; the other half, now present as 
potassium cyanate, being determined by boiling the cvanate with 
dilute sulphuric acid and titrating the ammonia produced. 

An alternative method is to pass the mixture into a solution of 
ammonium hydroxide or carbonate. After titration with a silver 
solution, the ammonium cyanate is converted into carbamide, 
and isolated and weighed as such. 

Cyanogen prepared in the usual way always contains HCN, 
which can be removed by passing the gas over cotton wool 
moistened with a silver solution. 


294 


APPENDIX B. 


Estimation of Benzol in Gas. 

Messrs Hoffmann and Kiispert found that benzol, with an 
ammoniacal solution of cyanide of nickel, forms a bluish-white 
precipitate, consisting of an equal number of molecules 
of cyanide of nickel, ammonia, and benzol. The benzol is 
held in so firm a combination that it cannot be displaced 
either by cold water or by ammonia, though it can be taken 
out by large quantities of ether. On boiling with water or 
cyanide solution the benzol is set free. In the absence of 
ammonia no such precipitate is formed; and an ammoniacal 
solution of nickel hydrate gives no results. Dennis and O’Neill, 
unwilling to work with poisonous cyanide of nickel, found that an 
ammoniacal solution of nitrate of nickel works equally well; and 
their solution is made of 14 grams of nitrate of nickel, nitric acid 
(sp. gr. 1.44) 2 c.c., water 160 c.c., to form a solution, which 
is then slowly poured into 100 c.c. ammonia of sp. gr. 0.908. 
The solution is now ready for use, but it is better to let it 
stand for some hours to allow a little double salt to crystallise 
out. 

The gas is shaken up with the solution in a Hempel pipette, 
but as it picks up ammonia from the solution, and increases a 
little in bulk, it has therefore to be then shaken up with 10 per 
cent, sulphuric acid to remove this ammonia. The final volume 
shows by difference the volume of benzol absorbed. 


APPENDIX C. 


WEIGHTS AND MEASURES. 

The Weights and Measures Act of 1897 made the use of the 
metric system permissible in the trade of the United Kingdom, 
but unfortunately, owing to various circumstances, this permission 
has not been taken advantage of. 

The Board of Trade standards are derived from the standard 
metre and the standard kilogramme, and the imperial equivalents 
of these are given by Order of Council dated 19th May 1898, 
and are as follows :— 

1 metre = 39.370113 inches. 

1 „ = 3.280843 feet. 

1 „ = 1.0936143 yards. 

1 kilogramme = 2.2046223 lbs. 

1 „ =i543 2 -35 grains. 

From the metre all other measures and weights are derived. 

Deka, hecto, kilo mean respectively ten, a hundred, a 
thousand; and deci, centi, milli mean respectively a tenth, a 
hundredth, a thousandth. 


Liquid — 

1 cubic centimetre = 1 gram of water at 4 0 Cent. 

1 kilogramme = the weight of 1 litre of water at 4 0 Cent. 



APPENDIX C. 


296 


Liquid — 
1 litre 


1 litre 
1 gallon 
1 gram 

1,000 kilogrammes 
16 oz. 

0.0648 gram 


= 100 centilitres = 10 decilitres = y 1 ^ dekalitre = 
y i_ hectolitre = 1000.16 cubic centimetres ; 
or in English measure, 

= 1.75980 pints or 0.22 gallon. 

= 4*5459 6 3 i litres. 

= i5-43 2 grains. 

= 0.9482 ton. 

= 1 lb. = 7,000 grains = 0.45359243 kilogramme. 
= 1 grain. 


lb. (Avoirdupois) = 453-593 grams. 


Cubic Measure- 


1,728 cubic inches = 1 cubic foot. 
27 „ feet =1 „ yard. 


Useful Memoranda — 

Weight of a cubic foot of hydrogen 


= 37- 1 5 grains. 


)) 

}J 

JJ 

carbonic acid 

= 

817.30 


)> 

)) 

>5 

sulphuretted hydrogen 

= 

631.54 

)» 


>> 

1) 

ammonia 

= 

3 1 5-7 7 


}) 

>> 

) J 

carbonic oxide 

= 

520.10 

5 ) 

5 ) 

5 J 

55 

marsh gas 

= 

297.20 

>> 

>5 

>> 


nitrogen 

= 

520.10 

>> 

>5 


JJ 

olefiant gas 

= 

520.10 



>> 

)> 

air 

= 

535-96 

J> 

)» 


5 > 

oxygen 

— 

594.40 

>> 

>» 

>> 

>> 

water vapour 

= 

334-35 

>> 

>) 

>5 

)) 

bisulphide of carbon 

= 

1411.70 



In order to obtain the weight of a cubic foot of any gas whose 
molecular formula is known, calculate the molecular weight; 
divide this by 2, and multiply by the weight of 1 cubic foot of 
hydrogen (37.15). This will give the weight in grains of 1 cubic 
foot of the gas. 


Example — 

The molecular weight of carbonic acid = 442 = 22. 
22 x 37.15 = 817.30 grains per cubic foot. 




COMPARISON OF THERMOMETERS. 


297 


Comparison of Thermometers. 


Centi¬ 

grade. 

Fahren¬ 

heit. 

Centi¬ 

grade. 

Fahren¬ 

heit. 

Centi¬ 

grade. 

Fahren¬ 

heit. 

Centi¬ 

grade. 

+ 260 

4 500.0 

+ 225 

+ 437-Q 

+ 190 

+ 374-0 

+ 155. 

259 

498.2 

224 

435-2 

189 

372.2 

154 

258 

496.4 

223 

433-4 

188 

370-4 

153 

257 

494.6 

222 

431.6 

187 

368.6 

152 

256 

492.8 

221 

429.8 

186 

366.8 

151 

255 

491.O 

220 

428.0 

185 

365-0 

150 

254 

489.2 

219 

426.2 

184 

363-2 

I49 

253 

487.4 

218 

424.4 

183 

361.4 

148 

252 

485.6 

217 

422.6 

182 

359-6 

147 

251 

483.8 

2l6 

420.8 

l8l 

357-8 

146 

250 

482.O 

215 

419.0 

180 

356.0 

145 

249 

480.2 

214 

417.2 

179 

354-2 

I44 

248 

478.4 

213 

415-4 

178 

352-4 

143 

247 

476.6 

212 

413.6 

177 

350-6 

I42 

246 

474.8 

211 

411.8 

176 

348.8 

141 

245 

473-o 

210 

410.0 

175 

347-o 

I40 

244 

471.2 

209 

408.2 

174 

345-2 

139 

243 

469.4 

208 

406.4 

173 

343-4 

138 

242 

467.6 

207 

404.6 

172 

341.6 

137 

24I 

465.8 

206 

402.8 

171 

339-8 

136 

24O 

464.0 

205 

401.0 

170 

338.0 

135 

239 

462.2 

204 

399-2 

169 

336.2 

134 

238 

460.4 

203 

397-4 

168 

334-4 

133 

2 37 

458.6 

202 

395-6 

167 

332-6 

132 

236 

456.8 

201 

393-8 

166 

330.8 

131 

235 

455-o 

200 

392.0 

165 

329.0 

130 

234 

453-2 

199 

390.2 

164 

327.2 

I29 

233 

451-4 

198 

388.4 

163 

325-4 

128 

232 

449.6 

197 

386.6 

162 

323-6 

12 7 

231 

447.8 

196 

384.8 

l6l 

321.8 

126 

230 

446.0 

195 

383-0 

l6o 

320.0 

125 

229 

444.2 

194 

381.2 

159 

318.2 

124 

228 

442.4 

193 

379-4 

158 

3 i6 -4 

123 

227 

440.6 

192 

377-6 

157 

314.6 

122 

226 

438.8 

191 

375-8 

156 

312.8 

12 I 


Fahren¬ 

heit. 


+ 311.0 

309.2 
307-4 
305-6 
303-8 

302.0 

300.2 

298.4 

296.6 

294.8 

293.O 

291.2 

289.4 

287.6 

285.8 

284.0 

282.2 

280.4 

278.6 

276.8 

275-o 

273.2 

271.4 

269.6 

267.8 

266.0 

264.2 

262.4 

260.6 

258.8 

257.0 

255-2 

253-4 

251.6 

249.8 






























298 


APPENDIX C. 


Comparison of Thermometers— Continued. 


Centi¬ 

grade. 

Fahren¬ 

heit. 

Centi¬ 

grade. 

Fahren¬ 

heit. 

Centi¬ 

grade. 

Fahren¬ 

heit. 

Centi¬ 

grade. 

Fahren¬ 

heit. 

+ 120 

+ 248.O 

+ 85 

+ 185.O 

4-50 

+ 122.0 

+ 15 

+ 59.O 

119 

246.2 

84 

183.2 

49 

120.2 

H 

57-2 

Il8 

244.4 

83 

181.4 

48 

118.4 

13 

55-4 

1 17 

242.6 

82 

179.6 

47 

II6.6 

12 

53-6 

Il6 

240.8 

8l 

177.8 

46 

114.8 

II 

51.8 

115 

239.O 

80 

176.O 

45 

II 3.0 

IO 

5 °-° 

114 

237.2 

79 

174.2 

44 

III .2 

9 

48.2 

113 

235-4 

78 

172.4 

43 

IO9.4 

8 

46.4 

112 

233.6 

77 

170.6 

42 

IO7.6 

7 

44.6 

III 

231.8 

76 

168.8 

4 i 

IO5.8 

6 

42.8 

no 

230.0 

75 

167.O 

40 

IO4.O 

5 

41.0 

109 

228.2 

74 

165.2 

39 

102.2 

4 

39-2 

108 

226.4 

73 

163.4 

38 

IOO.4 

3 

37-4 

107 

224.6 

72 

l6l.6 

37 

98.6 

2 

35-6 

106 

222.8 

7 i 

159-8 

36 

96.8 

1 

33-8 

105 

221.0 

70 

158.O 

35 

95 -o 

Water 

freezes 

0 

320 

104 

219.2 

69 

156.2 

34 

93-2 

- I 

30.2 

103 

217.4 

68 

154-4 

33 

91.4 

2 

28.4 

102 

215.6 

67 

152.6 

32 

89.6 

3 

26.6 

101 

213.8 

66 

150.8 

3 1 

87.8 

4 

24.8 

Water 

boils 

100 

212.0 

65 

149.0 

30 

86.0 

5 

23.0 

99 

210.2 

64 

147.2 

29 

84.2 

6 

21.2 

98 

208.4 

63 

145.4 

28 

82.4 

7 

19.4 

97 

206.6 

62 

143.6 

27 

80.6 

8 

17.6 

96 

204.8 

61 

141.8 

26 

78.8 

9 

15-8 

95 

203.0 

60 

140.0 

25 

77.0 

10 

14.0 

94 

201.2 

59 

138.2 

24 

75-2 



93 

199.4 

58 

136.4 

23 

73-4 


... 

92 

197.6 

57 

134.6 

22 

71.6 


... 

9 i 

195.8 

56 

132.8 

21 

69.8 


... 

90 

194.0 

55 

131-0 

20 

68.0 



89 

192.2 

54 

129.2 

19 

66.2 


... 

88 

190.4 

53 

127.4 

18 

64.4 



87 

188.6 

52 

125.6 

17 

62.6 


... 

86 

186.8 

5 i 

123.8 

16 

60.8 


... 


Conversion of Thermometer Degrees. 

0 Cent, to 0 Fahr., multiply by 9, divide by 5, then add 32. 

0 Fahr. to 0 Cent., first subtract 32, then multiply by 5, and divide by 9. 




































COMPARISON OF DIFFERENT HYDROMETERS. 299 


Comparison of Different Hydrometers. 


(Degrees according to Baum'e and Tivaddell, with the 
Specific Gravities.) 


B. 

T. 

Specific 

Gravity. 

B. 

T. 

Specific 

Gravity. 

B. 

T. 

Specific 

Gravity. 

0.0 

0.0 

I.OOO 

17.7 

28.0 

1.140 

32.8 

59 -o 

I.295 

0.7 

1.0 

I.005 

18.0 

28.4 

1.142 

33 -o 

59-4 

I.297 

1.0 

I.4 

I.007 

'H 

29.O 

I -145 

33*3 

60.0 

I.300 

1.4 

2.0 

I.OIO 

18.8 

30.0 

1.150 

33-7 

61.0 

I -305 

2.0 

2.8 

1.014 

19.0 

30.4 

I.I 52 

34 -o 

61.6 

I.308 

2.1 

3 -o 

1.015 

19-3 

31.0 

I - I 55 

34-2 

62.0 

1.310 

2.7 

4.0 

1.020 

19.8 

32.O 

1.160 

34-6 

63.0 

I -315 

3 -o 

4.4 

1.022 

20.0 

32.4 

1.162 

35 -o 

64.0 

I.320 

3-4 

5 -o 

1.025 

20.3 

33 -o 

1.165 

35-4 

65.0 

1-325 

4.0 

5.8 

I.O29 

20.9 

34 -o 

1.170 

35-8 

66.0 

i- 33 o 

4.1 

6.0 

I.030 

21.0 

34-2 

1.171 

36.0 

66.4 

i -332 

4-7 

7.0 

1-035 

21.4 

35-0 

1 .175 

36.2 

67.0 

i -335 

5 -o 

7-4 

I.O37 

22.0 

36.0 

1.180 

36.6 

68.0 

1.340 

5-4 

8.0 

I.O4O 

22.5 

37 -o 

1.185 

37-0 

69.0 

1-345 

6.0 

9.0 

I.O45 

23.0 

38.0 

1.190 

37-4 

70.0 

i. 35 o 

6.7 

10.0 

I.050 

23-5 

39 -o 

1 .195 

37-8 

71.0 

1-355 

7.0 

10.2 

I.O52 

24.0 

40.0 

1.200 

38.0 

71.4 

1-357 

7-4 

11.0 

1-055 

24-5 

41.0 

1.205 

38.2 

72.0 

1.360 

8.0 

12.0 

1.060 

25.0 

42.0 

1.210 

38.6 

73-0 

1.365 

8.7 

13.0 

1.065 

25-5 

43 -o 

1-215 

39 -o 

74.0 

i. 37 o 

9.0 

13-4 

1.067 

26.0 

44.0 

1.220 

39-4 

75 -o 

i -375 

9-4 

14.0 

1.070 

26.4 

45 -o 

1.225 

39-8 

76.0 

1.380 

10.0 

15.0 

1.075 

26.9 

46.0 

1.230 

40.0 

76.6 

1.383 

10.6 

16.0 

1.080 

27.0 

46.2 

1.231 

40.1 

77 -o 

1-385 

11.0 

16.6 

1.083 

27.4 

47.0 

1.235 

40.5 

78.0 

1.390 

11.2 

17.0 

1.085 

27.9 

48.0 

1.240 

40.8 

79.0 

1-395 

11.9 

18.0 

1.090 

28.0 

48.2 

1.241 

41.0 

79-4 

1-397 

12.0 

18.2 

1.091 

28.4 

49.0 

1.245 

41.2 

80.0 

1.400 

12.4 

19.0 

1.095 

28.8 

50.0 

1.250 

41.6 

81.0 

1.405 

13.0 

20.0 

1.100 

29.0 

50.4 

1.252 

42.0 

82.0 

1.410 

13.6 

21.0 

1.105 

29-3 

51.0 

1.255 

42.3 

83.0 

1-415 

14.0 

21.6 

1.108 

29.7 

52.0 

1.260 

42.7 

84.0 

1.420 

14.2 

22.0 

1.no 

30.0 

52.6 

1.263 

43 -o 

84.8 

1.424 

14.9 

23.0 

1.115 

30.2 

53 -o 

1.265 

43 -i 

85.0 

1.425 

15.0 

23.2 

1.116 

30.6 

54 -o 

1.270 

43-4 

86.0 

1.430 

15-4 

24.0 

1.120 

31.0 

54-8 

1.274 

43-8 

87.0 

1-435 

16.0 

25.0 

1.125 

3 1 - 1 

55 -o 

1.275 

44.0 

87.6 

1.438 

16.5 

26.0 

1.130 

3 i -5 

56.0 

1.280 

44.1 

88.0 

1.440 

17.0 

26.8 

I -134 

32.0 

57 -o 

1.285 

44.4 

89.0 

1-445 

17.1 

27.0 

I - I 35 

32.4 

58.0 

1.290 

44.8 

90.0 

1.450 




















3 oo 


APPENDIX C. 


Comparison of Different Hydrometers— Continued. 


B. 

T. 

Specific 

Gravity. 

B. 

T. 

Specific 

Gravity. 

B. 

T. 

Specific 

Gravity. 

45-o 

90.6 

1*453 

54-o 

H9-4 

1-597 

6l.8 

150.0 

1-750 

45-i 

91.0 

1-455 

54-i 

120.0 

1.600 

62.0 

150.6 

i-753 

45-4 

92.0 

1.460 

54-4 

121.0 

1.605 

62.1 

151.0 

1-755 

45-8 

93-o 

1.465 

54-7 

122.0 

1.610 

62.3 

152.O 

1.760 

46.0 

93-6 

1.468 

55-o 

123.0 

1.615 

62.5 

i53-o 

1-765 

46.1 

94.0 

1.470 

55-2 

124.0 

1.620 

62.8 

154.0 

1.770 

46.4 

95-o 

1-475 

55-5 

125.0 

1.625 

63.O 

x 55-o 

i-775 

46.8 

96.0 

1.480 

55-8 

126.0 

1.630 

63.2 

156.0 

1.780 

47-0 

96.6 

1.483 

56.0 

127.0 

i -635 

63.5 

i57.o 

1.785 

47.1 

97.0 

1.485 

56.3 

128.0 

1.640 

63-7 

158.0 

1.790 

47-4 

98.0 

1.490 

56.6 

129.0 

1.645 

64.O 

i59-o 

1-795 

47.8 

99.0 

1-495 

56.9 

130.0 

1.650 

64.2 

160.0 

1.800 

48.0 

99.6 

1.498 

57-0 

130.4 

1.652 

64.4 

161.0 

1.805 

48.1 

100.0 

1.500 

57-i 

131-0 

i -655 

64.6 

162.0 

1.810 

48.4 

101.0 

1-505 

57-4 

132.0 

1.660 

64.8 

163.0 

1.815 

48.7 

102.0 

1.510 

57-7 

i33-o 

1.665 

65.O 

164.0 

1.820 

49.0 

103.0 

I-5I5 

57-9 

134.0 

1.670 

65.2 

165.0 

1.825 

49.4 

104.0 

1.520 

58.0 

134.2 

1.671 

65-5 

166.0 

1.830 

49-7 

105.0 

1-525 

58.2 

i35-o 

i -675 

6 5-7 

167.0 

i -835 

50.0 

106.0 

i-53o 

58.4 

136.0 

1.680 

65-9 

168.0 

1.840 

50-3 

107.0 

i-535 

58.7 

137.0 

1.685 

66.0 

168.4 

1.842 

50.6 

108.0 

1.540 

58.9 

138.0 

1.690 

66.1 

169.0 

1.845 

50.9 

109.0 

i-545 

59-o 

138.2 

1.691 * 

66.3 

170.0 

1.850 

51.0 

109.2 

1.546 

59-2 

139 0 

1.695 

66.5 

171.0 

1.855 

51.2 

IIO.O 

i-55o 

59 -5 

140.0 

1.700 

66.7 

172.0 

1.860 

5i-5 

III.O 

i-555 

59-7 

141.0 

1.705 

67.0 

173-0 

1.865 

51-8 

112.0 

1.560 

60.0 

142.0 

1.710 




52.0 

112.6 

1.563 

60.2 

143.0 

I-7I5 




52.1 

II3.0 

1-565 

60.4 

144.0 

1.720 




52.4 

I I4.O 

i-57o 

60.6 

145.0 

1.725 




52.7 

115.0 

1-575 

60.9 

146.0 

1.730 1 




53-0 

II6.O 

1.580 

61.0 

146.4 

1-732 




53-3 

117.0 

1-585 

61.1 

147.0 

1-735 ! 




53-6 

Il8.0 

1.590 

61.4 

148.0 

1.740 1 




53-9 

119.0 

1-595 

61.6 

149.0 

x -745 1 





N.B .—The Baume degrees are calculated by the formula— 


d— —^ 4-3 water of 15 0 Cent. 

144 . 3 -N 

being put = o°, and sulphuric acid of 1.842 at 15 0 Cent. = 66°. 

Compare Lunge’s ^ Sulphuric Acid and Alkali,” vol. i., p. 20. 

This is the Baume’s hydrometer, mostly used on the Continent of Europe, 
but other scales are in use there as well, and quite another scale for Baume’s 
hydrometer is used in America. 

































SPECIFIC GRAVITY, SPECIFIC HEAT OF GASES. 3OI 


Specific Gravity and Weights of Gases. 


Description. 

Specific 

Gravity 

(air=i,oit) 

Weight 
per 100 
cub. ft. 

Description. 

Specific 

Gravity 

(air=i,ooc) 

Weight 
per 100 
cub. ft. 



lbs. 



lbs. 

Air 

I. OOO 

7.66 

Coal-gas 

O.5OO 

3- 8 3 

Aqueous vapour - 

O.633 

4^5 

Hydrochloric acid - 

1.247 

9.55 

Ammonia 

O.589 

4.51 

Hydrogen 

O.069 

0-53 

Carbonic acid 

I.529 

II .71 

Marsh gas 

O.562 

4*30 

,, oxide 

O.967 

7.4I 

Nitric oxide - 

1.039 

7-95 

Carburetted hydro¬ 



Nitrous oxide 

1.527 

11.70 

gen, heavy 

O.978 

7-49 

Nitrogen 

O.97I 

7-44 

Carburetted hydro¬ 



Olefiant gas - 

O.982 

7 . 5 2 

gen, light - 

0-557 

4.26 

Oxygen 

1.105 

8.46 

Chlorine 

2.470 

18.92 

Steam, gaseous 

0.622 

4.76 


Specific Heat. 

The Specific Heat of a body is the ratio of the quantity of heat required to 
raise that body i° to the quantity required to raise an equal weight of water i°. 
Example :—Water is the standard = 1. The specific heat of mercury is .033. 
Therefore the quantity of heat required to heat 1 lb. of mercury i° Fahr. 
would heat 1 lb. of water .033° Fahr.; or the quantity of heat required to 
heat 1 lb. of water i° Fahr. would heat 30 lb. of mercury i° Fahr. 


Table of Specific Heats. 


Water 

. 

I.OOO 

Carbonic acid - 0.216 and 0.171 

Acetic acid 

- 

0.659 

,, oxide - 0.248 

and 0.177 

Acetone vapour 

- 

0.413 

Chalk 

0.215 

Air 

- *0.238 

and 0.169 

Charcoal, wood 

0.241 

Alcohol 


0.659 

,, animal - 

0.261 

,, vapour 

- 

0-453 

Chlorine gas 

0.121 

Aluminium 

- 

0.234 

Clay 

0.185 

Ammonia gas 

- 

0.508 

Coal (anthracite) - 

0.201 

,, liquor 

(sp. gr. 


,, (bituminous) - 

0.241 

1.024)- 

- 

0.887 

Coke (increases as tem¬ 


Beeswax 

- 

0-45 

perature rises) - 

0.203 

Benzene 

- 

0-394 

Copper 

0.095 

Benzol 

- 

0.381 

Creosote 

0.458 

,, vapour 

- 

0-375 

Ether 

0.521 

Binoxide of nitrogen 

0.231 

,, vapour 

0.481 

Birch wood - 

- 

0.48 

Ethylene gas 

0.404 

Bisulphide carbon vapour - 

0.157 

Glass 

0.194 

Brass 

- 

0.094 

Gold 

0.032 

Brickwork - 

- 

0.192 

Graphite 

0.202 

„ fire 

- 

0.22 

Hydrochloric acid (sol.) 

0.600 

Bromine vapour 

- 

0.056 

„ (gas) - 

0.185 

Carbon 

- 

0.241 

Hydrogen - - 3.405 and 2.410 


* Where two specific heats are given for a gas, these are the specific 
heats for the gas at constant pressure and at constant volume respectively. It 
takes .238 B.T.U. to heat a pound of air i° Fahr. when it is allowed to expand 
so as to keep the pressure constant, and only . 169 B.T.U. to do the same when 
the gas is prevented from doing so. The reason is that no heat is, in the 
latter case, expended in doing external work. 



















APPENDIX C. 


302 


Table of Specific Heats— Continued. 


Ice - 

0.504 

Iron, cast - 

0.130 

,, wrought 

0. no 

Lead 

0.031 

Lime, burned 

0.217 

Magnesium 

0.250 

Marble, white 

0.216 

Marsh gas - 

0-593 

Mercury 

0.033 

Nitric oxide 

0.232 

Nitrogen - 

- 0.244 and 0.174 

Nitrous oxide 

0.226 

Oil, olive - 

0.310 

Oxygen gas 

- 0.218 and 0.156 

Petroleum - 

0-434 

Phosphorus 

0.250 

Pine 

0.65 

Platinum - 

0.034 

Potassium - 

0.167 

Silver 

0.056 


Spermaceti - - 0.32 

Steam (saturated at con¬ 
stant volume) - 0.305 

,, (gas) - 0.475 and 0.370 
Steel - - - 0.117 

Stonework- - - 0.197 

Sulphur - - - 0.203 

Sulphuretted hydrogen - 0.243 

Sulphuric acid, density 1.87 0.335 

»> >> ,, 1-30 0.661 

Sulphurous anhydride - 0.155 

Tar, sp. gr. 1.176 - - 0.288 

Tin - - - 0.056 

Turpentine oil - - 0.416 

,, vapour- - 0.506 

Water at 32 0 Fahr.- - 1.000 

,, 212 0 Fahr. - - 1.013 

Wood (average) - - 0.550 

,, spirit - - 0.601 

Zinc - - - 0.093 


Specific Gravity and Weights of Various Liquids. 


Various. 

Oils. 


Specific 

Weight in lbs. 


Specific 

Weight in lbs. 

Description. 

Gravity 



Description. 

Gravity 



(Water 

Cubic 

Per 

(Water 

Cubic 

Per 


= 1). 

feet. 

gallon. 


= 1,000). 

feet. 

gallon. 

Acid— 




Almond oil (59 0 




Hydrochloric 

I.27 

75 

12.7 

Fahr.) - 

O.918 

57 

9.18 

Nitric - 

1.22 

75 

12.2 

Castor oil 

O.97 

60 

9-7 

Sulphuric 

I.84 

ii 5 

18.4 

Cod liver oil 

O.92 

57 

9.2 

Alcohol— 




Essential oil of 




Absolute 

0.80 

5 o 

8.0 

bitter almonds 

I.O49 

65 

IO.49 

Proof - 

O.92 

57 

9.2 

Essential oil of 




Ammonium, 




turpentine 

O.864 

54 

8.64 

liquid - 

0-73 

4 S 

7-3 

Fat, animal 

O.92 

57 

9.2 

Benzene - 

O.85 

53 

8-5 

Lard oil - 

O.9I 

57 

9.1 

Benzol 

O.85 

53 

8.5 

Linseed oil (53 0 




Mercury (at 32 0 




Fahr.) - 

O.94 

59 

9.4 

Fahr.) - 

13.59 

847 

135-9 

Mineral lubri¬ 




Milk 

I.03 

64 

IO.3 

cating oil 

O.89 

55 

8.9 

Naphtha, coal - 

O.85 

53 

8.5 

Neatsfoot oil - 

O.91 

57 

9-1 

,, wood 

O.80 

50 

8.0 

Olive oil - 

O.92 

57 

9.2 

Petroleum 

0.88 

55 

8.8 

Paraffin oil 

0.82 

51 

8.2 

Water— 




,, spirit - 

O.78 

49 

7.8 

Distilled 

1.000 

62 

10.0 

Rape and colza 




Rain - 

1.001 

62 

10.01 

oil 

O.91 

57 

9 -i 

Sea 

1.026 

64 

10.26 

Tallow 

O.94 

59 

9-4 

Wine, say 

1.014 

63 

10.14 

Train oil - 

0-93 

58 

9-3 





Turpentine 

O.87 

54 

8.7 




















DENSITIES OF GASES AND VAPOURS. 303 

Densities and Weights of Gases and Vapours. 


( Winkler and Lunge’s “ Technical Gas Analysis.”) 


Name of Gas. 

Molecular 

Formula. 

Density. 
(Hydrogen = i.) 

1 Litre of Gas 
in the Normal 
State weighs 

Acetylene 

Benzene - * - 

Butylene - 
Carbon disulphide 
,, oxysulphide 

Cyanogen - 

Ethane .... 
Hydrogen cyanide 

Phosphoretted hydrogen - 
Propylene 

Silicium tetrafluoride 

c 2 h 2 

C 6 H 6 

c 4 h 8 

cs 2 

co 2 s 

(CN) 2 

c 2 h 6 

HCN 

h 3 p 

C 3 H 6 

SiF 4 

12.970 
38.910 
27.940 
37-965 
29-955 
25.990 

14.970 
13-495 
16.980 
20.955 

52.055 

Grammes. 

1.1621 

3-4863 

2.5034 

3-4017 

2.6839 

2.3287 

1.2413 

1.2091 
I-52I4 
1-8775 
4.6641 


Specific Gravities and Weights of Gases and Vapours. 

(“Alkali Maker’s Handbook .”) 


North latitude, 52 0 30', 130 feet above sea level. 


Gas. 

Symbol. 

Mole- 

cular 

Weight. 

Specific 

Gravity 

(Air=i). 

Grains per 
cub. ft. 29.92" 
and 32° Fahr. 

Lbs. per cub. 

foot 29.92" 
and 32 0 Fahr.* 

Ammonia - 

NH 3 

17.0 

0.58890 

332.96 

-04757 

Atmospheric air - 



I. OOOOO 

565.16 

.08074 

Bromine - 

Br 2 

160.0 

5 - 5227 I 

3122.1 

.4460 

Chlorine - 

CL, 

71.0 

2.4492I 

I 384-73 

.1978 

Carbonic oxide - 

CO 

28.0 

O.96709 

546.78 

.07811 

,, anhydride - 

C0 2 

44-0 

I.51968 

859.21 

.12274 

Ethylene - 

c,h 4 

28.0 

0.96744 

546.98 

.07814 

Hydrogen - 

h 2 

2.0 

O.06923 

39-1439 

.OO55919 

,, chloride 

HCL 

36-5 

I.25922 

711.94 

.1017 

Iodine 

I 2 

254.O 

8.756 

4949.90 

.7071 

Methane - 

ch 4 

16.0 

0.55297 

312.64 

.04466 

Mercury - 

Hg 

200.0 

... 

39 I 4.39 

•5592 

Nitrogen - 

n 2 

28.0 

O.970IO 

548.47 

.07835 

Nitrous oxide 

N 2 0 

44.O 

I.52269 

860.90 

.1229 

Nitric oxide 

NO 

30.0 

I.03767 

586.66 

.08381 

Nitrous anhydride 

n 2 o 3 

76.0 

2.630 

1487.46 

•2125 

Nitric peroxide - 

no 2 

46.O 

1.592 

900.31 

.1286 

99 99 

n 2 o 4 

92.0 

3.184 

1800.63 

•2572 

Oxygen 

0 2 

32.0 

I.IO52I 

624.85 

.08926 

Sulphuretted hydrogen 

h 2 s 

34-0 

I.I7697 

665.44 

.09506 

Sulphurous anhydride - 

so 2 

64.O 

2.21295 

1251.19 

.1787 

Sulphur 

s 2 

64.O 

2.2155 

I252.59 

.1789 

Water 

h 2 o 

18.0 

0.62182 

351-57 

.05022 


* For calculations with large quantities of gas, it is sufficiently accurate to 
assume that 10,000 cub. ft. weigh as many cwt. as the molecular weight of 
the gas divided by 4 indicates. 

For example, 10,000 cub. ft. of sulphuretted hydrogen weigh - 3 ^ = 8.5 
cwt. (exactly, it would be 8.488 cwt.). 























304 


APPENDIX C. 


Specific Gravities of Liquor Ammonia at 15 0 Cent. 

(Lunge and Wiernik.) 


Specific 
Gravity 
at 15 0 . 

Per cent. 

nh 3 . 

1 Litre con¬ 
tains grms. 

nh 3 . 

Correction 
of the 
Specific 
Gravity for 

+ i° c. 

Specific 
Gravity 
at 15°. 

Per cent. 

nh 3 . 

1 Litre con¬ 
tains grms. 

nh 3 . 

Correction 
of the 
Specific 
Gravity for 
-j-i° C. 

I. OOO 

0.00 

0.0 

0.00018 

O.94O 

I 5-63 

146.9 

O.OOO39 

O.998 

0.45 

4-5 

O.OOOlS 

0.938 

16.22 

152.1 

O.OOO4O 

O.996 

0.91 

9.1 

O.COO19 

0.936 

16.82 

157.4 

O.OOO4I 

O.994 

i -37 

13.6 

0.00019 

0.934 

17.42 

162.7 

O.OOO4I 

O.992 

1.84 

18.2 

0.00020 

O.932 

18.03 

168.1 

O.OOO42 

O.990 

2.31 

22.9 

0.00020 

O.930 

18.64 

173.4 

O.OOO42 

O.988 

2.80 

27.7 

0.00021 

0.928 

19.25 

178.6 

O.OOO43 

O.986 

3-30 

32.5 

0.00021 

O.926 

19.87 

184.2 

O.OOO44 

O.984 

3.80 

37-4 

0.00022 

O.924 

20.49 

189.3 

O.OOO45 

O.982 

4-30 

42.2 

0.00022 

O.922 

21.12 

194-7 

O.OOO46 

O.980 

4.80 

47.0 

O.OOO23 

O.920 

21-75 

200. I 

O.OOO47 

O.978 

5-30 

51.8 

O.OOO23 

0.918 

22.39 

205.6 

O.OOO48 

O.976 

5.80 

56.6 

O.OOO24 

0.916 

23.03 

210.9 

O.OOO49 

O.974 

6.30 

61.4 

0.00024 

O.914 

23.68 

216.3 

O.OOO50 

O.972 

6.80 

66.1 

0.00025 

O.912 

24-33 

221.9 

O.OOO51 

O.970 

7.31 

70.9 

0.00025 

O.9IO 

24.99 

227.4 

O.OOO52 

O.968 

7.82 

75-7 

0.00026 

0.908 

25.65 

232.9 

O.OOO53 

O.966 

8.33 

80.5 

0.00026 

0.906 

26.31 

238.3 

O.OOO54 

O.964 

8.84 

85.2 

0.00027 

O.904 

26.98 

243.9 

O.OOO55 

O.962 

9-35 

89.9 

0.00028 

O.902 

27.65 

249.4 

O.OOO56 

0.960 

9.91 

95 -i 

0.00029 

O.900 

28.33 

255-0 

O.OOO57 

O.958 

10.47 

100.3 

0.00030 

O.898 

29.OI 

260.5 

O.OOO58 

0.956 

11.03 

105.4 

0.00031 

O.896 

29.69 

266.0 

O.OOO59 

0-954 

11.60 

110.7 

O.OOO32 

0.894 

30.37 

271.5 

0.00060 

O.952 

12.17 

II 5-9 

O.OOO33 

O.892 

31.05 

277.0 

0.00060 

O.950 

12.74 

121.0 

O.OOO34 

0.890 

31-75 

282.6 

0.00061 

O.948 

I 3 - 3 I 

126.2 

O.OOO35 

0.888 

32.50 

288.6 

O.OOO62 

O.946 

13.88 

131-3 

O.OOO36 

0.886 

33.25 

294.6 

O.OO063 

O.944 

14.46 

136.5 

O.OOO37 

0.884 

34.10 

301.4 

O.OOO64 

O.942 

15.04 

Hi -7 

O.OOO38 

0.882 

34-95 

308.3 

O.OO065 

















CALORIFIC POWER OF VARIOUS COMBUSTIBLES. 30$ 


Calorific Power of Various Combustibles. 


Constituent. 

B.T.U. 

C.U. 

Carbon to carbon dioxide 

Carbon to carbon monoxide - 
Hydrogen to water .... 

Methane to carbon dioxide and water 

Ethylene. 

Sulphur to sulphur dioxide 

Wood. 

Coal. 

Natural oil ----- - 

Coal-gas 

14,500 

4,327 

61,524 

24,513 

21,345 

3,891 

4,500 to 7,200 
11,1500 to 16,200 
18,000 
19,800 

8,080 

2,404 

34,180 

13,063 

11,858 

2,162 

2.500 to 4,000 

6.500 to 9,000 
10,000 
11,000 


Volumes of Water at Different Temperatures ( Kopp ). 


Temperature 

Centigrade. 

Volume. 

Temperature 

Centigrade. 

Volume. 

O 

I. 

21 

I.OOI776 

I 

O.999947 

22 

I. OOI995 

2 

O.999908 

23 

1.002225 

3 

O.999885 

24 

I.OO2465 

4 

O.999877 

25 

I.OO2715 

5 

O.999883 

30 

I.OO4064 

6 

O.999903 

35 

I.OO5697 

7 

O.999938 

40 

1.007531 

8 

O.999986 

45 

I. OO954I 

9 

I.OOOO48 

5 o 

I.OII766 

10 

I.OOOI24 

55 

I.OI4IOO 

11 

1.000213 

60 

I.016590 

12 

I. OOO314 

65 

I.OI9302 

13 

I.OOO429 

70 

I.022246 

14 

I.OOO556 

75 

I.025440 

15 

I.OO0695 

80 

I.O28581 

16 

I.OO0846 

85 

I.O31894 

1 7 

I.OOIOIO 

90 

1-035397 

18 

1.001184 

95 

1.039094 

19 

20 

1.001370 
1.001567 

100 

1.042986 


u 

















3o6 


APPENDIX C. 


Sulphuric Acid. 

Table of Specific Gravities, Weights, and Volumes, at 
Various Degrees Twaddell. 


{Lunge and Is lev .) 


Twaddell 

Specific 

Gravity. 

100 Parts by Weight contain 

1 Cubic Foot of Acid 6o° Fahr. 

at 6o° 
Fahr. 

so.,. 

h 2 so 4 . 

Weighs 
Lbs. Avd. 

Contains 

h.,so 4 . 

Yields 

Na 2 S 0 4 . 

40 

1.200 

22.30 

27.32 

74.82 

Lbs. 

20.44 

Lbs. 

29.62 

41 

1.205 

22.82 

27.95 

75 * 14 

21.00 

33*43 

42 

1.210 

23.33 

28.58 

75*45 

21-57 

31*25 

43 

1*215 

23.84 

29.21 

75*76 

22.14 

32.08 

44 

1.220 

24.36 

29.84 

76.07 

22.71 

32.90 

45 

1.225 

24.88 

30.48 

76.38 

23.28 

33*73 

46 

1.230 

25*39 

31.II 

76.69 

23.85 

34*55 

47 

1*235 

25.88 

31.70 

77.00 

24.4I 

35*37 

48 

I.24O 

26.35 

32.28 

77.32 

24.97 

36.18 

49 

I.245 

26.83 

32.86 

77.63 

25-54 

37.01 

50 

I.250 

27.29 

33*43 

77-94 

26.10 

37.82 

5 i 

1*255 

27.76 

34.00 

78.25 

26.66 

38.63 

52 

1.260 

28.22 

34*57 

78.56 

27.23 

39*45 

53 

1.265 

28.69 

35*14 

78.87 

27.79 

40.27 

54 

1.270 

29.15 

35-71 

79.19 

28.35 

41.08 

55 

i *275 

29.62 

36.29 

79*50 

28.92 

41.90 

56 

1.280 

30.IO 

36.87 

79.81 

29.48 

42.72 

57 

1.285 

30*57 

37-45 

80.12 

30.04 

43*53 

58 

1.290 

31.04 

38.03 

80.43 

30.60 

44*34 

59 

1.295 

31*52 

38.61 

80.74 

31*17 

45.16 

60 

1.300 

31*99 

39-19 

81.06 

31*74 

45*99 

61 

1*305 

32.46 

39-77 

8 i .37 

32.32 

46.83 

62 

1.310 

32*94 

40.35 

81.68 

32.89 

47.65 

63 

1*315 

33 * 4 i 

40.93 

81.99 

33.46 

48.48 

64 

1.320 

33*88 

41.50 

82.30 

34-03 

49.31 

65 

1*325 

34*35 

42.08 

82.62 

34.60 

50.13 

66 

1-330 

34.80 

42.66 

82.93 

35 -18 

50.98 

67 

i *335 

35*27 

43*20 

83.24 

35*79 

51.86 

68 

1.340 

35 * 7 i 

43*74 

83*55 

36.40 

52.74 

69 

i *345 

36.14 

44.28 

83.86 

37*01 

53*63 

70 

1*350 

36.58 

44.82 

84.17 

37.63 

54.52 

7 i 

i *355 

37.02 

45-35 

84.49 

38.24 

55 * 4 i 

72 

1.360 

37*45 

45*88 

84.80 

38.85 

56.29 

73 

1.365 

37.89 

46.41 

85.11 

39.46 

57 -18 

74 

i* 37 o 

38.32 

46.94 

85.42 

40.07 

58.05 

75 

i *375 

38.75 

47*47 

85*73 

40.68 

58.94 

76 

1.380 

39.18 

48.00 

86.04 

41.29 

59.83 

77 

1*385 

39.62 

48.53 

86.36 

4 I * 9 I 

60.72 

78 

1.390 

40.05 

49.06 

86.67 

42.52 

61.61 

79 

1*395 

40.48 

49-59 

86.98 

43.13 

62.50 

80 

1.400 

40.91 

50.11 

87.29 

43*74 

63.38 

81 

1.405 

41*33 

50.63 

87.60 

44*36 

64.27 

82 

1.410 

41.76 

5 i.i 5 

87.92 

44*97 

65*13 

83 

1*415 

42.17 

51.66 

88.23 

45.58 

66.02 

84 

1.420 

42*57 

52.15 

88.54 

46.18 

66.90 

85 

1.425 

42.96 

52.63 

88.85 

46.78 

67.78 

86 

1.430 

43*36 

53-11 

89.16 

47.38 

68.65 

87 

M 35 

43*75 

53*59 

89.47 

47*99 

69.53 






















SPECIFIC GRAVITY OF SULPHURIC ACID. 307 


Sulphuric Acid— Continued . 


Twaddell 

Specific 

Gravity. 

100 Parts by Weight contain 

1 Cubic Foot of Acid 6o° Fahr. 

at 60° 
Fahr. 

so.,. 

h 2 so 4 . 

Weighs 
Lbs. Avd. 

Contains 

H 2 S 0 4 . 

Yields 

Na 2 S 0 4 . 

88 

I.44O 

44.I4 

54.07 

89.79 

Lbs. 

48.59 

Lbs. 

70.41 

89 

1-445 

44-53 

54.55 

90. IO 

49.19 

71.28 

90 

1.450 

44.92 

55.03 

9O.4I 

49-79 

72.15 

91 

1-455 

45-31 

55.50 

90.72 

50.39 

73-01 

92 

1.460 

45-69 

55-97 

91.03 

5°.'99 

73.88 

93 

1.465 

46.07 

56.43 

91.35 

51-159 

74.76 

94 

1.470 

46.45 

56.90 

91.66 

52.i19 

75.62 

95 

i -475 

46.83 

57-37 

91.97 

5279 

76.49 

96 

1.480 

47.21 

57.83 

92.28 

53-39 

77-3 6 

97 

1.485 

47-57 

58.28 

92.59 

54-00 

78.25 

98 

1.490 

47-95 

58.74 

92.90 

54.60 

79.12 

99 

1-495 

48.34 

59.22 

93.22 

55-20 

79.98 

100 

1.500 

48.73 

59-70 

93-53 

55-84 

80.92 

IOI 

1.505 

49.12 

60.18 

93.84 

56.47 

81.82 

102 

1.510 

49.51 

60.65 

94-15 

57 -Jo 

82.74 

103 

I- 5 I 5 

49.89 

61.12 

94.46 

5773 

83.65 

104 

1.520 

50.28 

6 i .59 

94.77 

58.36 

84.56 

105 

1-525 

50.66 

62.06 

95.09 

59-00 

85-50 

106 

i- 53 ° 

51.04 

62.53 

95-40 

59-62 

86.39 

107 

1-535 

51-43 

63.00 

95.71 

60.26 

87.32 

108 

1.540 

5 I -78 

63.43 

96.02 

60.89 

88.23 

109 

i -545 

52.12 

63.85 

96.33 

61.52 

89.15 

no 

i- 55 o 

52.46 

64.26 

96.65 

62.15 

90.06 

III 

1-555 

52.79 

64.67 

96.96 

62.78 

90.97 

112 

1.560 

53-12 

65.08 

97.27 

63.42 

91.90 

113 

1-565 

53-46 

65.49 

97.58 

64.05 

92.81 

114 

1-570 

53 - 8 o 

65.90 

97.89 

64.68 

93-72 

115 

1-575 

54-13 

66.30 

98.20 

65-31 

94.64 

Il6 

1.580 

54.46 

66.71 

98.52 

65-94 

95-54 

11 7 

1-585 

54.80 

67-13 

98.83 

66.58 

96.48 

118 

1.590 

55-18 

67.59 

99.14 

67.21 

97.40 

119 

1-595 

55-55 

68.05 

99.45 

67.84 

98.30 

120 

1.600 

55-93 

68.51 

99.76 

68.47 

99.22 

121 

1.605 

56.30 

68.97 

IOO.07 

69.10 

100.15 

122 

1.610 

56.68 

69.43 

IOO.39 

6974 

101.05 

123 

1.615 

57-05 

69.89 

IOO.70 

70.37 

101.95 

124 

1.620 

57-40 

70.32 

IOI.01 

71.07 

102.96 

125 

1.625 

57-75 

70.74 

IOI.32 

71.77 

104.00 

126 

1.630 

58.09 

71.16 

IOI.64 

72.46 

105.00 

127 

1-635 

58.43 

71-57 

IOI.95 

73.16 

106.00 

128 

1.640 

58.77 

71.99 

102.26 

73-85 

107.00 

129 

1.645 

59.10 

72.40 

102.57 

74-55 

108.00 

130 

1.650 

59-45 

72.87 

102.88 

75-25 

109.05 

131 

1.655 

59-78 

73-23 

103.19 

75-94 

110.04 

132 

1.660 

60.11 

73-64 

103.50 

76.64 

in.05 

133 

1.665 

60.46 

74.07 

103.82 

77-33 

112.05 

134 

1.670 

60.82 

74.51 

104.13 

78.03 

H 3. 0 5 

135 

1.675 

61.20 

74-97 

104.44 

78.73 

114.10 

136 

1.680 

6 i .57 

75-42 

104.75 

79.42 

115.10 

137 

1.685 

61.93 

75.86 

105.07 

80.12 

116.10 

138 

1.690 

62.29 

76.30 

105.38 

80.81 

117.10 

139 

1.695 

62.64 

76.73 

105.69 

81.51 

118.10 

140 

1.700 

63:00 

77.17 

106.00 

82.21 

119.15 























3°8 


APPENDIX C. 


Sulphuric Acid— Co?itinued. 


Twaddel 

' Specific 
Gravity. 

ioc Parts by Weight contaii 

1 1 Cubic Foot of Acid 6o° Fahr. 

at 6o° 

Fahr. 

S 0 3 . 

h 2 so 4 . 

Weighs 
Lbs. Avd. 

Contains 

h 2 so 4 . 

Yields 

Na,S 0 4 . 

141 

1-705 

63.35 

77.60 

106.31 

Lbs. 

82.90 

Lbs. 

120.15 

142 

1.710 

63.70 

78.04 

106.62 

83.60 

I 2 I.I 5 

143 

I- 7 IS 

64.07 

78.48 

IO6.94 

84.29 

122.15 

I44 

1.720 

64.43 

78.92 

IO7.25 

84.99 

123.15 

145 

1-725 

64.78 

79.36 

IO7.56 

85.69 

124.20 

146 

I.73O 

65.14 

79.80 

107.87 

86.38 

125.20 

147 

148 

1-735 

65-50 

80.24 

108.18 

87.08 

126.20 

1.740 

65.86 

80.68 

108.49 

87.77 

127.20 

149 

1-745 

66.22 

81.12 

108.80 

88.47 

128.20 

150 

i- 75 ° 

66.58 

81.56 

I09. J 2 

89.17 

I29.20 

151 

i -755 

66.94 

82.00 

109-43 

89.86 

130.20 

152 

1.760 

67.30 

82.44 

109.74 

90.56 

131.20 

153 

1-765 

67.65 

82.88 

110.05 

91.25 

132.25 

154 

1.770 

68.02 

83-32 

110.36 

91-95 

I 33-25 

155 

* i -775 

68.49 

83.90 

110.68 

92.88 

I34.60 

156 

1.780 

68.98 

84.50 

110.99 

93 . 8 i 

135-90 

157 

1.785 

69-47 

85.10 

hi.30 

94-74 

137-30 

158 

1.790 

69.96 

85.70 

hi.61 

95-67 

138.50 

159 

1-795 

70.45 

86.30 

hi.92 

96.60 

I4O.OO 

160 

1.800 

70.94 

86.90 

112.23 

97-52 

I4I.30 

l6l 

1.805 

71.50 

87.60 


.. . 

162 

1.810 

72.08 

88.30 


... 


163 

1.815 

72.69 

89.05 

. . • 



164 

1.820 

73 - 5 i 

90.05 

. . . 



... 

1.821 

73-63 

90.20 




. . . 

1.822 

73-80 

90.40 





1.823 

73.96 

90.60 





1.824 

74.12 

90.80 

... 

.. . 


165 

1.825 

74-29 

91.00 





1.826 

74-49 

91.25 




... 

1.827 

74.69 

91.50 





1.828 

74-86 

91.70 





1.829 

75-03 

91.90 


•. • 


166 

1.830 

75-19 

92.10 



... 


1.831 

75-35 

92.30 

... 


... 


1.832 

75-53 

92.52 





1.833 

75-72 

92-75 




... 

1.834 

75.96 

93-05 

.. . 


... 

167 

i -835 

76.27 

93-43 




... 

1.836 

76.57 

93.80 




... 

i -837 

76.90 

94.20 


.. • 


... 

1.838 

77 -23 

94.60 


.. . 



1.839 

77-55 

95-00 




168 

1.840 

78.04 

95 - 6 o 


. • • 


... 

1.840 

78.33 

95-95 



... 

... 

1.841 

79.19 

97.00 

.. . 

.. • 

... 

... 

1.841 

79-76 

97.70 


• • • 



1.841 

80.16 

98.20 

... 



... 

1.840 

80.57 

98.70 




... 

1.840 

80.98 

99.20 




... 

1.839 

81.18 

99-45 

• • • 



... 

1.839 

81.39 

99.70 

... 



... 

1.838 

81.59 

99-95 

... 


... 




































CAUSTIC POTASH AND SODA SOLUTIONS. 309 


Specific Gravity and Percentage of Caustic Potash 


in Aqueous Solution. 


Specific 
Gravity at 
15 0 Cent. 

Per¬ 
centage 
of KOH. 

Specific 
Gravity at 
15 0 Cent. 

Per¬ 
centage 
of KOH. 

Specific 
Gravity at 

15 0 Cent. 

Per¬ 
centage 
of KOH. 

Specific 
Gravity at 
15° Cent. 

Per¬ 
centage 
of KOH. 

I.OO9 

I 

1.166 

19 

1-374 

37 

I.604 

55 

I.OI7 

2 

1.177 

20 

1.387 

38 

1.6l8 

56 

I.025 

3 

1.188 

21 

1.400 

39 

I.630 

57 

1-033 

4 

I.198 

22 

1.412 

40 

I.642 

58 

1.04I 

5 

I.209 

23 

1.425 

4i 

1-655 

59 

I.O49 

6 

1.220 

24 

1.438 

42 

I.667 

60 

I.058 

7 

I.23O 

25 

1.450 

43 

1.68l 

61 

I.065 

8 

1.24I 

26 

1.462 

44 

I.695 

62 

I.074 

9 

1.252 

27 

1-475 

45 

I .705 

63 

I.083 

10 

I.264 

28 

1.488 

46 

I.718 

64 

I.092 

11 

I.276 

29 

1.499 

47 

I.729 

65 

I.IOI 

12 

1.288 

30 

1.511 

48 

I.74O 

66 

I.no 

13 

1.300 

31 

1-525 

49 

1-754 

67 

1.119 

14 

I. 3 H 

32 

1-539 

50 

I.768 

68 

1.128 

15 

I.324 

33 

1.552 

5i 

I.780 

69 

1.137 

16 

1-336 

34 

1.565 

52 

1.790 

7 o 

1.146 

i 7 

1-349 

35 

1.578 

53 



1.155 

18 

I.361 

36 

1-590 

54 




Specific Gravity and Percentage of Caustic Soda 
in Aqueous Solution. 


Specific 
Gravity at 
15 0 Cent. 

Per¬ 
centage 
of NaOH. 

Specific 
Gravity at 
15° Cent. 

Per¬ 

centage 

ofNaOH. 

Specific 
Gravity at 
15 0 Cent. 

Per¬ 

centage 

ofNaOH. 

Specific 
Gravity at 
15 0 Cent. 

Per¬ 

centage 

of 

NaOH. 

I. 122 

IO 

1.392 

27 

I.638 

43 

I.842 

59 

I.I36 

II 

I.404 

28 

I.650 

44 

I.854 

60 

1 .152 

12 

I.422 

29 

I.662 

45 

I.864 

61 

1.166 

13 

I.438 

30 

I.674 

46 

I.874 

62 

1.182 

14 

1-454 

31 

1.686 

47 

1.888 

63 

1.196 

15 

1.462 

32 

1.702 

48 

I.896 

64 

1.214 

l6 

1.488 

33 

1.716 

49 

I.9OO 

65 

1.232 

1 7 

1.502 

34 

1.728 

50 

I.918 

66 

I.248 

18 

1.518 

35 

1.740 

5 i 

I.928 

67 

1.262 

19 

1.532 

36 

i. 75 o 

52 

I.938 

68 

I.278 

20 

1.548 

37 

1.762 

53 

I.948 

69 

I.294 

21 

1.564 

38 

1.778 

54 

I.960 

70 

1.308 

22 

1.580 

39 

1.790 

55 

1.972 

7 1 

I.324 

23 

1-594 

40 

1.804 

56 

I.982 

72 

1.342 

24 

1.608 

41 

1.816 

57 

1.992 

73 

1.358 

25 

1.622 

42 

1.828 

58 

2.002 

74 

1-374 

26 


















































3io 


APPENDIX C. 


Tension of Aqueous Vapour for each Tenth of a Degree 
Centigrade from o° to 30° Cent. (Regnault). 


Tem¬ 

perature 

0 Cent. 

Tension 
in Mm. of 
Mercury. 

Tem¬ 

perature 

0 Cent. 

Tension 
in Mm. of 
Mercury. 

Tem¬ 

perature 

0 Cent. 

Tension 
in Mm. of 
Mercury. 

Tem¬ 

perature 

0 Cent. 

Tension 
in Mm. of 
Mercury. 

0.0 

4.6 

4.4 

6-3 

8.8 

8.5 

13-2 

11 .3 

O. I 

4.6 

4-5 

6-3 

8.9 

8.5 

13-3 

11.4 

0.2 

4-7 

4.6 

6.4 

9.0 

8.6 

13-4 

11 .5 

0-3 

4-7 

4-7 

6.4 

9.1 

8.6 

13-5 

11 .5 

0.4 

4-7 

4.8 

6.4 

9.2 

8.7 

13.6 

11.6 

0-5 

4.8 

4.9 

6-5 

9-3 

8.7 

13.7 

11 .7 

0.6 

4.8 

5 -o 

6-5 

9.4 

8.8 

13.8 

11.8 

0.7 

4.8 

5 -i 

6.6 

9-5 

8.9 

13.9 

11.8 

0.8 

4.9 

5-2 

6.6 

9.6 

8.9 

I4.0 

11.9 

0.9 

4.9 

5-3 

6-7 

9-7 

9.0 

14.1 

12.0 

1.0 

4.9 

5 A 

6-7 

9-8 

9.0 

I4.2 

12.1 

1.1 

5 -o 

5-5 

6.8 

9.9 

9.1 

14-3 

12.1 

1.2 

5 -o 

5-6 

6.8 

10.0 

9.2 

I4.4 

12.2 

i -3 

5 -o 

5-7 

6.9 

10.1 

9.2 

14.5 

12.3 

1.4 

5 -i 

5-8 

6.9 

10.2 

9-3 

14.6 

12.4 

i -5 

5 *i 

5-9 

7 -o 

10.3 

9-3 

I4.7 

12.5 

1.6 

5-2 

6.0 

7 -o 

10.4 

9.4 

14.8 

12.5 

i -7 

5-2 

6.1 

7.0 

10.5 

9-5 

I4.9 

12.6 

1.8 

5-2 

6.2 

7-1 

10.6 

9-5 

15-0 

12.7 

1.9 

5-3 

6 -3 

7 .i 

10.7 

9.6 

I 5 .I 

12.8 

2.0 

5-3 

6.4 

7-2 

10.8 

9-7 

15.2 

12.9 

2.1 

5-3 

6-5 

7-2 

10.9 

9-7 

15-3 

12.9 

2.2 

5-4 

6.6 

7-3 

11.0 

9.8 

15.4 

13.0 

2.3 

5-4 

6.7 

7-3 

11.1 

9.9 

15.5 

13.1 

2.4 

5-5 

6.8 

7-4 

11.2 

9-9 

15.6 

13.2 

2-5 

5-5 

6.9 

7-4 

ii -3 

10.0 

15-7 

13.3 

2.6 

5-5 

7 -o 

7-5 

11.4 

10.1 

15.8 

13.4 

2.7 

5.6 

7 -i 

7-5 

n -5 

10.1 

15.9 

13-5 

2.8 

5-6 

7-2 

7-6 

11.6 

10.2 

16.O 

13.5 

2.9 

5.6 

7-3 

7-6 

11.7 

10.3 

16.1 

13.6 

3 -o 

5-7 

7-4 

7-7 

11.8 

10.3 

16.2 

13.7 

3 -i 

5-7 

7-5 

7-8 

11 .9 

10.4 

16.3 

13.8 

3-2 

5-8 

7-6 

7.8 

12.0 

10.5 

16.4 

13-9 

3-3 

5-8 

7-7 

7-9 

12.1 

10.5 

16. s 

14.0 

3-4 

5-8 

7-8 

7-9 

12.2 

10.6 

16.6 

14.1 

3-5 

5-9 

7-9 

8.0 

12.3 

10.7 

16.7 

14.2 

3-6 

5-9 

8.0 

8.0 

12.4 

10.7 

16.8 

14.2 

3-7 

6.0 

8.1 

8.1 

12.5 

10.8 

16.9 

14.3 

3-8 

6.0 

8.2 

8.1 

12.6 

10.9 

17.0 

14.4 

3-9 

6.1 

0 3 

8.2 1 

12.7 

10.9 

17.1 

14-5 

4.0 

6.1 

8.4 

8.2 

12.8 

11.0 

17.2 

14.6 

4.1 

6.1 

8.5 

8-3 

12.9 

11.1 

17.3 

14.7 

4.2 

6.2 

8.6 

8-3 

13.0 

11.2 

17.4 

14.8 

4-3 

6.2 

8.7 

8.4 

i 3 -i 

11.2 

i 7-5 

14.9 





















TENSION OF AQUEOUS VAPOUR. 


311 


Tension of Aqueous Vapour— Continued . 


Tem¬ 
perature 
* Cent. 

Tension 
in Mm. of 
Mercury. 

Tem¬ 

perature 

0 Cent. 

Tension 
in Mm. of 
Mercury. 

Tem¬ 
perature 
° Cent. 

Tension 
in Mm. of 
Mercury. 

Tem¬ 

perature 

0 Cent. 

Tension 
in Mm. of 
Mercury. 

17.6 

15.0 

20.8 

18.3 

23.9 

22.1 

27.O 

26.5 

17.7 

I 5 -I 

2O.9 

18.4 

24.O 

22.2 

27.I 

26.7 

17.8 

15.2 

21.0 

18.5 

24.I 

22-3 

27.2 

26.8 

17.9 

15-3 

21.1 

18.6 

24.2 

22.5 

27-3 

27.O 

18.O 

I S -4 

21.2 

18.7 

24.3 

22.6 

27.4 

27.I 

18.1 

15-5 

21.3 

18.8 

24.4 

22.7 

27-5 

27-3 

18.2 

15.6 

21.4 

19.0 

24-5 

22.9 

27.6 

27.5 

18.3 

15.7 

21.5 

19:1 

24.6 

23.O 

27.7 

27.6 

18.4 

15.8 

21.6 

19.2 

24.7 

23.I 

27.8 

27.8 

18.6 

15-9 

21.7 

19*3 

24.8 

23*3 

27.9 

27.9 

18.7 

16.0 

21.8 

19.4 

24.9 

23.4 

28.O 

28.1 

18.8 

16.1 

21.9 

19-5 

25.0 

23-5 

28.1 

28.3 

18.9 

16.2 

22.0 

19.7 

25-1 

23.7 

28.2 

28.4 

19.O 

16.3 

22.1 

19.8 

25.2 

23.8 

28.3 

28.6 

I 9 .1 

16.4 

22.2 

19.9 

2 5-3 

24.0 

28.4 

28.8 

19.2 

16.6 

22-3 

20.0 

25.4 

24.1 

28.5 

28.9 

19-3 

16.7 

22.4 

20.1 

25-5 

24-3 

28.6 

29.1 

19.4 

16.8 

22.5 

20.3 

25.6 

24.4 

28.7 

29-3 

19-5 

16.9 

22.6 

20.4 

25-7 

24.6 

28.8 

29.4 

19.6 

17.0 

22-7 

20.5 

25.8 

24.7 

28.9 

29.6 

19.7 

17. 1 

22.8 

20.6 

2 5*9 

24.8 

29.O 

29 8 

19.8 

17.2 

22.9 

20.8 

26.0 

25.0 

29.I 

30.0 

19.9 

17.3 

23.O 

20.9 

26.1 

25.1 

29.2 

30.1 

20.0 

17.4 

23.I 

20.0 

26.2 

25-3 

29*3 

30.3 

20.1 

17-5 

23.2 

21.1 

26.3 

25-4 

29.4 

30-5 

20.2 

17.6 

23.3 

21.3 

26.4 

25.6 

29-5 

30-7 

20.3 

17.7 

23.4 

21.4 

26.5 

25-7 

29.6 

30.8 

20.4 

17.8 

23-5 

21.5 

26.6 

25-9 

29.7 

31.0 

20.5 

17.9 

23.6 

21.7 

26.7 

26.0 

29.8 

31.2 

20.6 

18.0 

23.7 

21.8 

26.8 

26.2 

29.9 

3 i -4 

20.7 

18.2 

23-8 

21.9 

26.9 

26.4 




Example :— 

Find the amount of aqueous vapour in gas at 50° Fahr. (io° Cent.). 

Find the tension in mm. of mercury by table, divide by 760 mm. and you 
have the percentage of aqueous vapour; multiply by 100 = grains per 100 
cub. ft. 

Find weight of a cubic foot of aqueous vapour = H 2 0 = 18-^2 = 9x37 = 333. 
760)9.200(1.20 per cent. 

1,000,000 cub. ft. of gas x 1.2= 1,200,000. 

1,200,000 x 1 2 -r 70,000 = 57.08 gallons aqueous vapour per million cub. ft. 




































312 


APPENDIX C. 


Loss of Illuminating Power by Admixture of Air. 


(Dr E. G. Lowe.) 


Percentage of 
Air in 
Mixture. 

Loss of 
Illuminating 
Power. 

Loss of Illumin¬ 
ating Power for 

1 per cent. Air. 

Percentage of 
Air in 
Mixture. 

Loss of 
Illuminating 
Power. 

Loss of Illumi¬ 
nating Power 
for 1 per cent. 
Air. 


Per cent. 

Per cent. 


Per cent. 

Per cent. 

2.82 

5-7 2 

2.03 

I 7-65 

44-30 

2.5.I 

4.94 

10.08 

2.O4 

19.84 

51.19 

2.58 

5-40 

11.24 

2.08 

21.56 

56.69 

2.63 

8.51 

18.04 

2.12 

22.22 

58.88 

2.65 

8.95 

19.06 

2.13 

24. l6 

64.51 

2.67 

9.62 

21.16 

2.20 

27.69 

72.82 

2.63 

IO.4O 

23.24 

2.24 

3 I -30 

80.44 

2-5 7 

11.20 

26.66 

2.38 

32.95 

83.36 

2-53 

12-35 

29.02 

2-35 

34-53 

87.02 

2.52 

I2.8l 

30.48 

2.38 

37.50 

90.37 

2.41 

15-25 

37.66 

2.47 

4O.79 

93.82 

2.30 

16.98 

42.28 

2.49 



... 


Experiments carried out on 25-27 candle water-gas with a Bray’s Slit 
Union No. 7 Burner, with a regulated consumption of 5 cub. ft. per hour. 


Maximum Vapour Pressures of Naphthalene. 


(By W. R. Allan, M.A.) 


Tempera¬ 

ture 

0 Fahr. 

Corresponding 

Vapour 

Pressure. 

Weight of 
Naphthalene 
Saturating 

100 cub. ft. of Gas. 

Tempera¬ 

ture 

0 Fahr. 

Corresponding 

Vapour 

Pressure. 

Weight of 
Naphthalene 
Saturating 

100 cub. ft. of Gas. 


Mm. 

Grains. 


Mm. 

Grains. 

32 

0.022 

6.0 

158 

3-95 

IO50.O 

41 

O.034 

9.8 

167 

5-43 

I43O.O 

50 

O.O47 

14.1 

176 

7-4 

1898.O 

59 

0.062 

I9.0 

185 

9-8 

2426.O 

68 

0.080 

24.6 

194 

12.6 

3035.0 

77 

0.103 

30.9 

203 

15.5 

3727.O 

86 

0.135 

39-5 

212 

18.5 

4420.O 

95 

0.210 

57-5 

221 

22.4 


104 

O.32O 

83.5 

230 

27.3 


1 13 

0.510 

132.0 

239 

32.4 


122 

0.810 

208.0 

248 

40.2 


131 

1.260 

3 i 7 .o 

2 57 

49.8 


140 

I.83O 

482.0 

266 

61.9 


149 

2.650 

723.0 

... 














































SOLUBILITY OF GASES IN WATER. 


313 


Solubility of Gases in Water (by Volume) at a Pressure 
of 760 mm. (29.92 ins.). {Bunsen.) 


1 Vol. of 
Water 
Dissolves 
at 0 Cent. 

Am¬ 

monia. 

Atmos¬ 
pheric Air. 

Carbon 

Dioxide. 

Carbon 

Monoxide. 

Hydro¬ 

gen. 

Nitrogen. 

Oxygen. 

Sulphur¬ 

etted 

Hydro¬ 

gen. 

o° 

IO49.6 

O.O2471 

I.7967 

0.03287 

O.OI93 

0.02035 

O.O4114 

4.3706 

1° 

1020.8 

O.O2406 

1.7207 

O.03207 

O.OI93 

O.OI981 

O.O4OO7 

4.2874 

2° 

993-3 

O.02345 

I.6481 

O.03131 

O.OI93 

O.O1932 

O.O3907 

4-2053 

3 ° 

967.0 

O.O2287 

I -5787 

O.03057 

O.OI93 

0.01884 

0.03810 

4-1243 

4 ° 

941.9 

0.02237 

i- 5 I2 6 

0.02987 

O.OI93 

O.O1838 

O.O3717 

4.0442 

5 ° 

917.9 

0.02179 

1-4497 

O.02920 

O.OI93 

O.OI794 

O.03628 

3-9652 

6° 

895-0 

0.02128 

i -3901 

0.02857 

O.OI93 

O.O1752 

O.03554 

3.8872 

7 ° 

873 -i 

0.02080 

1-3339 

O.O2796 

O.OI93 

O.OI713 

O.03465 

3-8103 

8° 

852.1 

0.02034 

1.2809 

O.02739 

O.O193 

0.01675 

O.03389 

3-7345 

9 ° 

832.0 

O.OI992 

1.2311 

0.02686 

O.O193 

O.O164O 

O.03317 

3-6596 

xo° 

812.8 

O.OI953 

1.1847 

O.O2635 

O.OI93 

0.01607 

O.O3250 

3-5858 

ii° 

794-3 

O.OI916 

1.1416 

O.O2588 

O.O193 

O.O1577 

O.O3189 

3 - 5 I 32 

12° 

776.6 

0.01882 

1.1018 

O.02544 

O.O193 

O.OI549 

O.03133 

3 - 44 I 5 

13 ° 

759-6 

O.OI85I 

1.0653 

O.02504 

O.OI93 

O.OI523 

0.03082 

3-3708 

14 

743-1 

0.01822 

1.0321 

0.02466 

O.OI93 

0.01500 

O.03034 

3.3012 

1 5 ° 

727.2 

O.OI 795 

1.0020 

O.O2432 

O.O193 

O.OI478 

O.02989 

3.2326 

16 

711.8 

O OI 77 I 

0.9753 

O.02402 

O.OI93 

0.01458 

O.O2949 

3-1651 

1 7 ° 

696.9 

0.01750 

o. 95 I 9 

O.O2374 

O.OI93 

O.OI44I 

O.O2914 

3.0986 

18° 

682.3 

OOI732 

0.9318 

O.02350 

O.OI93 

O.OI426 

O.02884 

3-0331 

1 9 ° 

668.0 

O.OI717 

0.9150 

O.02329 

O.OI93 

O.OI423 

O.02858 

2.9687 

20° 

654.0 

O.OI704 

0.9014 

O.02312 

O.OI93 

O.OI403 

O.02838 

2.9053 


Atomic Weights. 



Sym¬ 

bol. 

Weight. 


Sym¬ 

bol. 

Weight. 

Aluminium 

A1 

27.1 

Fluorine - 

F 

19.OO 

Antimony 

Sb 

120.00 

Gallium - 

Ga 

70.00 

Argon (?) 

A 

40.00 

Germanium 

Ge 

72.00 

Arsenic - 

As 

75-00 

Gold - - - 

Au 

197.2 

Barium - 

Ba 

137-4 

Helium (?) 

He 

4.OO 

Beryllium 

Be 

9.1 

! Hydrogen 

H 

I.OI 

Bismuth - 

Bi 

208.5 

Indium - 

In 

II4.OO 

Boron 

B 

II.00 

Iodine 

I 

126.85 

Bromine - 

Br 

79.96 

Iridium - 

Ir 

I93.OO 

Cadmium 

Cd 

112.00 

Iron 

Fe 

56.OO 

Caesium - 

Cs 

113.00 

Lanthanium 

La 

I38.OO 

Calcium - 

Ca 

40.00 

Lead 

Pb 

206.9 

Carbon - 

C 

12.00 

Lithium - 

Li 

7 -03 

Cerium - 

Ce 

I4O.OO 

Magnesium 

Mg 

24.36 

Chlorine - 

Cl 

35-45 

Manganese 

Mn 

55 -oo 

Chromium 

Cr 

52.1 

Mercury - 

Hg 

200.3 

Cobalt 

Co 

59.00 

Molybdenum - 

Mo 

96.00 

Copper - 

Cu 

63.6 

Neodidymium (?) 

Nd 

144.00 

Erbium (?) 

Er 

166.00 

Nickel 

Ni 

58.7 





































314 


APPENDIX C. 


Atomic Weights— Continued . 



Sym¬ 

bol. 

Weight. 


Sym¬ 

bol. 

Weight. 

Niobium - 

Nb 

94.OO 

Sodium - 

Na 

23-05 

Nitrogen - 

N 

14.04 

Strontium 

Sr 

87.6 

Osmium - 

Os 

191.OO 

# Sulphur - 

S 

32.06 

Oxygen - 
Palladium 

O 

16.00 

Tantalum 

Ta 

183. CO 

Pd 

106.00 

Tellurium 

Te 

I27.OO 

Phosphorus 

P 

31-0 

Thallium - 

T 1 

204.1 

Platinum - 

1 Pt 

194-8 

Thorium - 

Th 

232.OO 

Potassium 

IC 

39-15 

Titanium - 

Ti 

48.I 

Praseodidymium (?) - 

Pr 

140.00 

Tin- 

Sn 

U8.5 

Rhodium - 

Rh 

103.00 

Tungsten 

W 

184.OO 

Rubidium 

Rb 

85.4 

Uranium - 

u 

239-5 

Ruthenium 

Ru 

101.7 

Vanadium 

V 

57-2 

Samarium (?) - 

Sa 

150.00 

Ytterbium 

Vb 

173.00 

Scandium 

Sc 

44.1 

Yttrium - 

Y 

89.00 

Selenium 

Se 

79.1 

Zinc 

Zn 

65-4 

Silicium - 
Silver 

Si 

Ag 

28.4 

107.93 

Zirconium 

Zr 

1 

90.6 


Percentage by Volume, Corresponding to the Weight 
in Grains of C0 2 per Cub. Ft. of Gas, at 
6o° Fahr. and 30-iN. Bar. 


Percentage 
by Volume. 

Grains C 0 2 
per Cub. Ft. 

Percentage 
by Volume. 

Grains CO., per 
Cub. Ft. 

Percentage 
by Volume. 

Grains CO., per 
Cub. Fd 

O. I 

O.817 

1.1 

8.987 

2.1 

17-157 

0.2 

I.634 

1.2 

9.807 

2.2 

17-974 

0-3 

2.451 

1-3 

10.621 

2-3 

18.791 

O.4 

3.268 

I.4 

II.438 

2.4 

19.608 

0-5 

4.C85 

i -5 

12.255 

2-5 

20.425 

0.6 

4.902 

1.6 

13.072 

2.6 

21.242 

0.7 

5-719 

i -7 

13.889 

2.7 

22.059 

0.8 

6.536 

1.8 

14.706 

2.8 

22.876 

0.9 

7-353 

1.9 

I 5-523 

2.9 

23.693 

1.0 

8.170 

2.0 

16.340 

3 -o 

24.510 










































PERCENTAGE BY VOLUME OF SH 2 ; NH S . 31 5 


Percentage by Volume, Corresponding to the Weight 
in Grains of SH 2 per Cub. Ft. of Gas, at 
6o° Fahr. and 30-iN. Bar. 


Percentage Grains SH 2 per 
by Volume. Cub. Ft”. 

Percentage 
by Volume. 

Grains SH« per 
Cub. Ft. 

Percentage 
by Volume. 

Grains SH 2 per 
Cub. Ft. 

O. I 

0.63 

1.1 

6.94 

2.1 

13.25 

0.2 

1.26 

1.2 

7-57 

2.2 

13.88 

0-3 

1.89 

1-3 

8.20 

2-3 

14.51 

0.4 

2.52 

1.4 

8.83 

2.4 

I 5 -H 

o -5 

3 -i 5 

i -5 

9.46 

2.5 

15.77 

0.6 

3-78 

1.6 

10.09 

2.6 

16.40 

0.7 

4.41 

i -7 

10.72 

2.7 

17.03 

0.8 

5-04 

1.8 

11-35 

2.8 

17.66 

0.9 

5-6 7 

1.9 

11.98 

2.9 

18.30 

1.0 

6.31 

2.0 

12.62 

3.0 

18.93 


Percentage by Volume, Corresponding to the Weight 
in Grains of NH 3 per Cub. Ft. of Gas, at 
6o° Fahr. and 30-m. Bar. 


Percentage 
by Volume. 

Grains NH 3 
per Cub. Ft. 

Percentage 
by Volume. 

Grains NH, 
per Cub. Ft. 

Percentage 
by Volume. 

Grains NH, per 
Cub. Ft'. 

O. I 

0.315 

1.1 

3.471 

2.1 

6.627 

0.2 

O.631 

1.2 

3.787 

2.2 

6.943 

0-3 

O.946 

1*3 

4.102 

2-3 

7.258 

0.4 

I.262 

1.4 

4.418 

2-4 

7-574 

0.5 

1.578 

1-5 

4-734 

2-5 

7.890 

0.6 

1.893 

1.6 

5.049 

2.6 

8.205 

0.7 

2.208 

1 -7 

5.365 

2.7 

8.521 

0.8 

2.524 

1.8 

5.680 

2.8 

8.836 

0.9 

2.840 

1-9 

5-996 

2.9 

9.152 

1.0 

3 .I 56 

2.0 

6.312 

1 

3.0 

9.468 





























316 


APPENDIX C. 


NOTES ON CALORIFIC VALUE. 

A gram-calorie is the amount of heat required to raise i gram 
of water i° Centigrade. 

A kilo-calorie is the amount of heat required to raise i kilo¬ 
gramme of water (i litre) i° Centigrade. 

A British Thermal Unit (B.Th.U.) is the amount of heat 
required to raise i lb. of water i° Fahrenheit. 

Calories per cubic foot are the number of kilogrammes of 
water (litres) raised through i° Cent, by complete combustion of 
i cubic foot of gas at N.T.P. 

Calories per cubic metre are the number of kilogrammes of 
water (litres) raised through i° Cent, by complete combustion of 
i cubic metre of gas. 

B.Th.U.’s per cubic foot are the number of lbs. of water 
which can be raised through i° Fahr. by complete combustion 
of i cubic foot of gas. 

To convert calories per cubic foot into B.Th.U.’s per cubic 
foot, multiply by 3.968 (3.97). 

To convert calories per cubic foot into calories per cubic 
metre, multiply by 35.316. 

To convert B.Th.U.’s per cubic foot into calories per cubic 
metre, multiply by 8.9. 

The calorific value of 1 lb. of fuel expressed in B.Th.U. is 
the Fahrenheit-lb. unit per lb. 

The amount of water which 1 lb. of fuel will evaporate, or 
the evaporative power per lb., is obtained from the calorific 
value of 1 lb. of fuel expressed in B.Th.U. divided by 967 
(latent heat of steam in degrees Fahr.). 

If a Centigrade thermometer is used, and it is desired to arrive 
at the evaporative value per lb., divide by 537 (latent heat of 
steam in degrees Cent.) instead of by 967. 

Example ;— 

1 lb. of fuel has a value of 11,800 B.Th.U.’s per lb., 
then 1 gram of fuel has a value of 11,800x1(6555.5) calories per gram ; 
or 1 lb. of fuel has a value of 11,800 x 9(6555.5) calories per lb. ; 

or 1 ton of fuel has a value of 11,800x1(6555.5) calories per ton, &c. 


INDEX. 


A BEL, Sir F., flash point apparatus, 
227, 228 

Absorption of gases by water, amount 

of, 313 

Acetic acid from destructive distilla¬ 
tion of peat, 9 

Acid, carbonic. See Carbonic Acid 
Acid, standard, for the estimation of 
ammonia in gas, 92 
standard, for the estimation of 
ammonia in gas liquor, 117 
Aerorthometer, Harcourt, 263, 269 
Air, effect on illuminating power, 312 
supply to retort furnaces, primary 
and secondary, 39, 40, 41, 43, 
44 

Alcohol ethyl, use of, in gas analysis, 

215 

Alkali, standard, for estimation of 
ammonia in gas liquor, 118 
Alkaline, washing of tar oils, working 
up of, 83, 84 

Allen, W. R., maximum vapour pres¬ 
sures of naphthalene, 312 
American gas oil, analysis of, 232 
Ammonia, action of, in purifiers, 150, 
288, 289 

by volume, corresponding to weight 
in grains of, 315 
combining weight, 2 
compounds in gas liquor, 114, 115 
from coke ovens, 112, 129 
in crude gas, estimation of, 92, 93 
in gas liquor, estimation of, 118 
in gas liquor, estimation of “ free,” 
120 


Ammonia in gas liquor, estimation of 
“fixed,” 121 
molecular weight, 2 
percentage of nitrogen in coal con¬ 
vertible, 113 
production of, 112 
solubility of, 313 
solution, standard, 4 
specific gravity of, 304 
symbol, 2 

Ammonium oxalate, 4 

sulphate, estimation of ammonia 
in, 90, 91 

sulphate, estimation of moisture 
in, 90 

sulphate, Fertilisers and Feeding 
Stuffs Act, relating to, 89 
sulphate, 4, 89, 90, 91 
thiocyanate, 4 

Analysis of gas, Bunte’s burettes for, 
212, 213, 214 

determination of benzene, 215, 
294 

determination of carbonic acid in 
coal-gas, 215 

determination of carbonic acid in 
waste, 46 

determination of carbonic oxide in 
coal, 216 

determination of carbonic oxide in 
waste, 47 

determination of hydrogen, 216, 
217, 218 

determination of hydrocarbon, 215, 
216 

determination of oxygen, 216 




INDEX. 


318 

Analysis, determination of oxygen in 
coal, 216 

determination of oxygen in waste, 
47 

determination of sulphur com¬ 
pounds, 99, 272, 273, 274 
furnace gases, 44 

“Orsat Muencke,” apparatus for, 
44 > 45 . 46 

oxygen needed for explosion in 
the, 216 

sampling furnace and waste gases, 
44 

Anthracene cake, estimation of anthra¬ 
cene in, 87 

Anthracite, composition of, 8 
Anthraquinone, formation of, from 
anthracene cake, 87 
Apparatus for determining flashing 
point of oil, 227, 228 
for gas analysis, 44, 215 
Aqueous vapour, tension of, 310, 311 
Argand burner No. 2, Metropolitan, 
260, 266, 267 

Arsenic, determination of, in coal and 
coke, 27, 28, 29, 30, 31 
Ash in coal and coke, determination of, 
25 

in various coals, 17, 18 
of fuel in lime, 102 
Assay of coal-tar, 81, 82, 83, 84 
Atomic weights, 313, 314 
Atmospheric air, solubility of, 313 


B ARIUM carbonate, combining 

weight, 2 

carbonate molecular weight, 2 
carbonate, symbol, 2 
hydrate, combining weight, 2 
hydrate, molecular weight, 2 
hydrate, standard solution, 4 
hydrate, symbol, 2 
Benzene in coal-gas, 215 

carbon bisulphide in, estimation 
of, 292, 293 


Benzene, distillation of, 88 
in oil-gas tar, 236 
sulphur in, estimation of, 293 
Bichromate of potassium, standard 
decinormal solution, 5 
of potassium, use of, for estimation 
of ferric oxide, 142 

Binks’ burette for testing ammoniacal 
liquor, 119 

Bituminous coal, composition of, 8 
Bivalent substances, 2 
Bog-ore (iron oxide), composition of, 
145 _ 

estimation of water in, 139 
estimation of iron in, 140 
estimation of organic matter, 140 
fouling of, 146 
hydrates, various, 138 
hydrates, calculations of, 149, 
150 

oxides, various, 138 
British thermal units, definition of, 197, 
316 

Bromine water, 5 

use of, in gas analysis, 215, 216 
Burner, Argand, for gas testing, 260, 
267 

flat flame, for gas testing, 260 
Bye-products of coal-gas tar, 75, 76, 77, 
78, 79, 80 

of oil-gas tar, 236, 237 


C ADMIUM chloride, solution for 
estimation of sulphuretted hydro¬ 
gen, 97, 98 

Caking coal, description of, 9 
Calcium carbonate, combining weight, 2 
molecular weight, 2 
symbol, 2 

Calcium hydrate, combining weight, 2 
molecular weight, 2 
symbol, 2 

standard solution, 5 
Calcium oxide, combining weight, 2 
molecular weight, 2 




INDEX. 


319 


Calcium symbol, 2 

in lime, estimation of, 106, 107 
Calorimeter for determining calorific 
value of gas, 200 

Boy’s official instrument, 199, 247, 
248, 274, 275, 276, 277, 278, 
279 

Junker’s apparatus, 203, 204 
Simmance-Abady apparatus, 198, 
200, 201, 202 

Calorific value, calculation of, from 
constituents, 205 
Calorific value of carbon, 48 

carbon monoxide, 48, 204, 205 
carburetted water-gas, 206 
coal-gas, 206 

Wigan Coal and Iron Co. Coals— 
Arley, 18 

Blackbrook little delph, 18 
Blackbrook, Rushy Park, 18 
Blackley little delph, 18 
Haigh, yard, 18 
Haigh, 5 feet, 18 
Lindsey Arley, 18 
Laffack, Rushy Park, 18 
Rushy Park mine, 18 
Wigan cannel, 18 
benzene, 204, 205 
butane, 204 
butylene, 204 
ethane, 204 
ethylene, 204, 205 
hydrogen, 48, 204, 205 
methane, 204, 205 
pentane, 204 
propane, 204 
sulphur, 48 
toluene, 204 

various Gas Companies’ gas, 203 
Candle a standard of light, 177 
balance, 182 
English sperm, 177 
rate of consumption of sperm, 183 
working out of results, 183, 184 
Cannel coal, 10 

calorific value, 32 
coke from, as fuel, 10 


Cannel Coal, Lesmahagow, 10 

Newbattle, composition of, 10 
Carbolic acid, estimation of, in coal-tar, 
82, 83 

Carbonic acid, estimation of, in coal- 
gas, 93, 97 

estimation of, in furnace gas, 44 
estimation of, in gas analysis, 215 
estimation of, in oil-gas, 93, 97 
estimation of, in waste gases, 47 
percentage by volume, 214 
reaction of, with incandescent car¬ 
bon, 48 

solubility of, 313 
Carbon heat units, 48 
Carbonate in lime and chalk, estima¬ 
tion of, 104, 105 
by Scheibler’s calcimeter, 103 
by Schrotter apparatus, 104 
Carbon bisulphide for estimating sul¬ 
phur in spent oxide, 174,175, 176 
in benzene, estimation of, 292, 293 
in gas, estimation of, 245, 247, 272, 
2 73> 274 

Carbonisation of coal-gas, production at 
various temperatures, 72 
effect of heat on gas and bye-pro¬ 
ducts, 71 
peat, 9 

Carburetted water gas, 225 

carbonic acid, estimation of, 93, 97 
composition of, 289 
specific gravity of oil used in, 225, 
227 

technical analysis of, 289 
Chloride of ammonium in gas liquor, 
122 

Chromate potassium. See Potassium 
Dichromate 
Coal analysis, 7, 1 7 > 18 
Coal analysis of Aston Hall premier 
coal, 17 
Arley, 18 

Arley, Lindsey, 18 
Blackley little delph, 18 
Blackbrook little delph, 18 
Blackbrook Rushy Park, 18 



320 


INDEX. 


Coal analysis of Birley silkstone, 17 
Derbyshire silkstone, 17 
Hazelwood Coal and Iron Co., 17 
Lidgate Colliery, 17 
Laffack, Rushy Park, 18 
Mirfield Coal Co., 17 
Newton Coat and Iron Co., 17 
Newton, Chamber, & Co.— 

1. Norfolk silkstone, 17 

2. Thin seam, 17 

3. Best silkstone, 17 

4. Screened gas coal, 17 

5. Silkstone soft, 17 
Pelton main, 17 
Pope & Pearson— 

1. Screened silkstone, 17 

2. Hard coal, 17 
Ravenhead upper delph, 17 
Rushy Park mine, 18 
Sheepbridge Coal and Iron Co., 17 
Staveley gas coal, top, 17 
Staveley gas coal, bottom, 17 
Unston Colliery Co., 17 

Wigan and Whiston gas coal, 17 
Wigan cannel, 18 
Wigan Coal and Iron Co., 18 
Woodleford gas coal, 17 
Coal caking, 9 
Coal, calorific value of, 18 

calorific value of pound water eva¬ 
porated per 1 lb. of fuel, 18 
cannel, 10 
compcsition of, 18 
experimentally testing of, 11-20 
estimation of ash in, 27 
estimation of arsenic, 27 
estimation of moisture, 21 
estimation of nitrogen, 27 
estimation of phosphorus, 24 
estimation of specific gravity, 26 
estimation of sulphur, 23 
estimation of volatile matter and 

fixed carbon, 26 
for gas making, 17 
Coal-gas, calorific value of, 206 

calorific value of, estimation of, 198, 

200, 203, 274-279 


Coal-gas, cyanides in, estimation of, 
101, 293 

cyanides in, extraction of, 99, 100 
hydrogen in, estimation of, 217 
nitrogen compounds, distribution 
of, 74 

specific gravity, estimation of, 218 
sulphuretted hydrogen in crude gas, 
94 , 95 

sulphuretted hydrogen in purified 
gas, 272 

sulphur compounds, 272, 274 
Coal-tar acid, washing of oil from, 83 
alkaline, washing of oil from, 84 
anthracene oil from, 84 
assay of, 81, 82, 83, 84 
carbolic acid from, 84 
free carbon, estimation of, 86 
light oils from, 83 
specific gravity, estimation of, 85 
Coefficient of expansion of oil, use of, 
226 

Coke as a fuel, 19 

ash in estimation of, 25, 26 
calorific value, 32-36 
estimation of arsenic, 27 
estimation of nitrogen, 27 
estimation of specific gravity, 26, 
27 

oven, ammonia from, 112 
Combustion, heat of various gases, 204, 
205 

Connecting rod for table photometer, 
260, 261 

pipe for table photometer, 261 
Constituents of coal-gas, 17, 18 
Consumption of gas in photometry, 
correction of volume, 270, 271 
Copper phosphate for estimating sul¬ 
phuretted hydrogen, 6, 94 
Creosote oil from coal tar, 84 
Cuprous chloride, use of, in gas analysis, 
216 

Cyanogen compounds in coal-gas, esti¬ 
mation of, 100 

estimation of, as Prussian blue, 
101 





INDEX. 321 


Cyanogen compounds in coal-gas, ex¬ 
tracting, various methods for, 99 
Cyanogen in purifying material and the 
influence of ammonia on its for¬ 
mation in purification, 288, 289 
test for, in presence of hydro¬ 
cyanic acid, 293 


D ARK screen for table photometer, 
264, 265 

Decomposition of woody fibre, 7 
Densities and weight of gases and 
vapours, 303 
Desiccator, use of, 23 
Designation of normal solution, 1 
Destructive distillation, products of, 
75-80 

Di-tri-ortho-phosphate, preparation of, 
6 

Direct fired setting, 37 

Disc, photometrical, 180 

Dust laying, use of oil-gas tar in, 237, 

238 


E FFECT of heat on ammonia, 71 
carbon disulphide, 71 
coke, 71 
cyanogen, 71 
gas production, 71, 7 2 
phenols, 71 
pitch, 71 
residuals, 73 

sulphuretted hydrogen, 71 
tar, 71, 72 

Effect of humidity on the pentane lamp, 
291, 292 

Eschka’s modification of process for 
estimation of sulphur in coal, 24 
Expansion of petroleum oil, coefficient 
of, 226 

Experimental coal-testing plant, 11 
description of, n, 12 
estimation of carbonic acid, 14, 16 

X 


Experimental estimation of sulphuretted 
hydrogen, 14, 16 
estimation of sperm value, 15 
sketch of, 13 
use of, 14, 15 
working data, 15 


F ahrenheit scale, 297,298 

Ferric oxide, 142 

Ferricyanide potassium, use as indi¬ 
cator, 143 

Ferrocyanide in gas liquor, estimation 
of, 133 

in spent oxide, estimation of, 290 
Ferrous sulphate solution for estimating 
manganese dioxide, 172 
Fertilisers and Feeding Stuffs Act, 1906, 
89 

Fery radiation pyrometer, description 
and use of, 59 

Fire-bricks and fireclays, 164 
method of analysis, 165 
estimation of alumina in, 166, 167 
estimation of calcium, 167 
estimation of ferric oxide, 166, 167 
estimation of magnesium, 167 
estimation of potassium, 168, 168 
estimation of silica in, 165 
estimation of sodium, 168, 169 
determination of specific gravity, 
169 

determination of volume weight, 
169 

determination of porosity, 169 
Fixed ammonia in gas liquor, 114, 121 
Flame, effect of humidity on the pen¬ 
tane, 291, 292 
Flame temperature, 206 
calculation of, 207, 209 
temperature of gases, 211 
temperature of liquid, 211 
temperature of solid, 211 
Flare lime, 102 
Flat flame burner, 260 
Furnace gases analysis, 47 




322 


INDEX. 


Furnace, regenerative, 39 

regenerative, primary and secon¬ 
dary air, 43, 44 


G AS analysis, 213 

Gas, calorific value of various 
gas companies, 203 
governor for table photometer, 250 
Gas liquor. See Liquor, Ammoniacal 
meter for table photometer, 250 
Gaseous firing, advantages of, 39 
Gases, waste, analysis of, 44 
Generator setting, 37, 41 
Governor, gas, 250 
Graphite, composition of, 8 


H ARCOURT’S, A. V., Aerortho- 
meter, 263, 269 

standard of light, 241, 251, 252 
Heat recorder, Watkins’ patent, 49, 50 
Seger’s cones, 51, 54 
Heisch & Hartley on Methven screen 
as standard light, 179 
Hochst test for anthracene, 87 
Humidity, effect of, on light of pentane 
flame, 291, 292 
Hydrated ferric oxides, 138 
estimation of, 149, 150 
experimental purification value, 
146, 147 

Hydrocarbon vapours in gas, estima¬ 
tion of, 215, 216 

Hydrogen in coal-gas, amount of, 205 
estimation of, 217 
Hydrogen heating value, 204 

sulphuretted, estimation of, 94, 95 
solubility of, 313 

Hydrochloric acid, combining weight, 2 
molecular weight, 2 
symbol, 2 

standard solution, 5 
Hydrometers, comparison of, 299, 300 


ILLUMINATING power of gas, 
1 supplied by London Gas Com¬ 
panies, 203 
calculated, 184, 185 
Referees’ instructions for testing, 
241, 244 

lost by admission of air, 312 
Impurities in coal-gas, 92 
Indicators, cochineal, 2 
lacmoid, 4 
litmus, 3 
methyl orange, 3 
phenolphthalein, 3 
potassium ferricyanide, 143 
turmeric, 118 

Inverse squares, law of, 177 
Iodine, combining weight, 2 

for determining sulphur in gas, 98 
molecular, 2 
solution, N/10, 5 
symbol, 2 

Iron oxide, analysis of, 138 

classification of various hydrates, 
150 

estimation of various hydrates, 149 
estimation of water in, 139 
estimation of organic matter, 140 
estimation of ferric oxide, 140, 145 
absorbing qualification, 146, 147 
estimation of ferrous oxide, 148 
various hydrates, 138 
various oxides, 138 


J UNKER calorimeter, 203, 204 


TZ JELDAHL’S process for estimating 
1V nitrogen, 27 


L ATENT heat of steam, 316 

Law of inverse squares in photo¬ 
metry, 177 




INDEX. 


323 


Lesmahagow cannel, 10 
Letheby’s specific gravity globe, 219 
Lewes, V. B., Prof., candles and 
calories, 205 

calorific value of pure coal-gas, 206 
calorific value of carburetted water- 
gas, 206 

illuminating power from blue water- 
gas, 212 

Lewes-Thompson’s calorimeter, de¬ 
scription, 32, 33 

Light measurement of the intensity of 
gas, 177 

Lignite, composition of, 8 
Lime, analysis of flare, 102 
analysis of, 105 

analysis of, estimation of total 
lime, 105 

analysis of, estimation of calcium, 
106, 107, 108 

analysis of, estimation of silica, 
108, 109 

analysis of, estimation of alumina, 
108, 109 

Liquid fuel for boilers, 237 
Liquor ammoniacal, 112 

ammonium salts, volatile at ordinary 
temperature, 114 

ammonium salts, fixed at ordinary 
temperature, 114 
analysis, 115 

analysis, use of Twaddel’s hydro¬ 
meter, 116 

analysis, estimation of total am¬ 
monia, Will’s test, 118 
analysis, estimation of free am¬ 
monia, 120 

analysis, estimation of fixed am¬ 
monia, 121 

analysis, estimation of carbonic 
acid, 121 

estimation of chlorides, 122 
estimation of sulphur, 122 
estimation of sulphocyanide, 123 
estimation of sulphide, 124 
estimation of sulphide and thio¬ 
sulphate, 124 


Liquor, estimation of total sulphur, 125 
estimation of sulphur as poly¬ 
sulphide, 125 

estimation of sulphite by poly¬ 
sulphide method, 126, 129 
distribution of sulphur, 129 
estimation of cyanogen compounds, 
130 

estimation of cyanide, 130 
estimation of ferrocyanide, 132 
estimation of thiocyanate, 133, 136 
the reaction of cyanide and poly¬ 
sulphide, 137 
List of testing places, 240 
Loan of apparatus for gas testing, 287 
London No. 2 Argand burner, 260, 
266 

Lunge on coal-tar and ammonia, 74, 
80 

Lux, F., specific gravity balance for 
gases, 221, 222 


M AHLER bomb calorimeter, 34, 35 
Manganese dioxide in Weldon 
mud, estimation of, 171, 172 
percentage, 171, 174 
Measuring rods for table photometer, 
264, 265, 267 
Meters, experimental, 250 
Methven screen, standard of light, 178 
dimensions of slot, 179 
Methyl orange indicator, 3 
Metropolitan Argand burner No. 2, 
260, 262 

Mirrors for table photometer, 264, 265, 
267 

Moisture in coal, determination of, 21 
coke, determination of, 21 
Monazite sands, analysis of, 291 


N AKAMURA’S method of estimat¬ 
ing sulphur in coal, 23 
Naphtha from coal-tar, 73 




INDEX. 


324 

Naphtha from peat, 9 
from oil-gas tar, 236 
Napthalene, estimation of, in oil-gas or 
coal-gas— 

by Colman & Smith test, 151- 

I55 . 

by Dickinson Gair’s modifica¬ 
tion, 155, 156 
by Somerville method, 156 
maximum vapour pressure, 312 
removal from gas, 157 
removal, Bell's method,.163 
removal, Botley method for, 159 
removal, C. Carpenter’s method, 
159, 160 

removal, Coulson method, 162, 

163 

removal, Young & Glover method, 
162 

Newcastle fire-clay, analysis of, 164 
Nitric acid, combining weight, 2 
molecular weight, 2 
symbol, 2 

Nitrogen in coal and coke, determina¬ 
tion of, 27 

in coal, distribution of, 113 
in coke, distribution of, 84 
solubility of, 313 
Non-caking coal, properties of, 9 
Non-volatile ammonia in gas liquor, 121 


O IL for gas making, analysis of, 
225 

coefficient of expansion, use of, 
227 

composition and valuation of, 233 
distillation, collection of, 230 
distillation, fractional, 229 
flash-point apparatus, Abel, 227 
flash-point apparatus, Pensky-Mar¬ 
ten, 228 

sample of American oil, 232 
sample of Russian oil, 231 
specific gravity, 225, 226 
specific gravity of fractions, 230, 

233 


Oil, table of constants obtained for pure 
hydrocarbons, 234 
table of gasification results, 235 
weight of fractions, method, 233 
Oil-gas tar, 236 

composition of, 236 
distillation of, 237 
for burning, 237 
for dust laying, 237, 238 
Olefines in coal-gas, 205 
One-twelfth of a cubic foot measure, 
281, 283 

Open 60-inch Letheby-Bunsen photo¬ 
meter, 181 

Orsat Muencke gas analysis apparatus, 
44 

use of, 45 

Ounces of ammonia in gas liquor, 116 
Oxide, ferric. See Iron Oxide 
Oxalic acid, combining weight, 2 
molecular weight, 2 
symbol, 2 

Oxygen in waste gases, 48 
solubility of, 313 


P ARAFFINS in coal-gas tar, 73 
Paraffins in oil-gas tar, 236 
Peat, acetic acid from, 9 
air dried, 8 
amount of water in, 8 
composition of, 8 
destructive distillation of, 9 
gas per ton, 8, 9 
illuminating power, 8, 9 
naphtha from, 9 
paraffin wax from, 9 
sulphate of ammonia from, 9 
tar from, 9 

Pentane, preparation and testing, 254, 

2 55 

provision of, 255, 256 
lamp, effect of humidity on, 291, 
292 

lamp, Harcourt standard, 251, 262 
Permanganate of potassium, decinois 
mal solution, 5 



INDEX. 


Permanganate of potassium, standard¬ 
ising solution, 142 
Phenanthracene, 78 
Phenols from coal-tar, 78, 84 
Phenolthalein solution, 3 
Phosphorus in coal, estimation of, 24, 

25 

Photometer, Letheby-Bunsen, open, 
181 

table, 257 

Photometrical disc, 180 

scale for table photometer, 260, 261 
sighting wheel for “ Flicker,” 187 
Photometry burner, 241, 244, 266, 
267 

calculation of results, 183, 184, 
241, 242, 243, 244 
candle balance, 182, 184 
Flicker photometer, 185, 188 
fundamental law of, 177 
generalised photometrical law, 177 
Lambert cosine law, 177 
law of inverse squares, 177 
street photometry, 189 
table for angles, 191 
table for longitudes and horizontal 
angles, 193-196 

5 cubic foot rate, explanation of, 

185 

16 candle basis, explanation of, 185 
Pitch, estimation of free carbon in, 86 
estimation of softening point, 84 
free carbon in, 86 
in coal-gas tar, 83 
specific gravity, 86 

Potassium dichromate, decinormal solu¬ 
tion, 5 

Potassium dichromate used in oxide of 
iron test, 144 

permanganate decinormal solu¬ 
tion, 5 

Potassium hydrate, combining weight, 2 
molecular weight, 2 
solution, specific gravity, and per¬ 
centage, 309 
standard solution, 5 
symbol, 2 


325 

Pounds of sperm per ton, method of 
working out, 15 

Pressure of gas, mode of testing, 249, - 
250, 280, 281 
regulation by gas tap, 258 
the gas governor, 258 
Primary air supply to retort setting, 38 
Prussian blue in spent oxide, 177 
by Feld method, 290, 291 
estimation of, in cyanogen liquor, 
IOI 

in gas liquor, 133 
Purity of pentane, 255, 256 
Pyrogallic acid, use of, in gas analysis, 
47, 216 

Pyrometers, Fery radiation, description 
and use of, 59, 60 
Siemens’ electrical, description and 
use of, 55, 59 

Wanner, description and use of, 
61, 62 


Q UALITY of gas from various gas 
companies, 203 


R EACTION between carbon and 
incandescent fuel, 48 
Referees’, Metropolitan Gas, apparatus 
for estimating sulphur in gas, 
245, 247, 273 

Argand gas burner No. 2, 267 
estimation of sulphuretted hydro¬ 
gen in gas, 272 

instruction for testing for illumi¬ 
nating power, 241-244 
instruction for testing with sperm 
candles, 182, 183 

prescription as to sulphuretted 
hydrogen in gas, 244, 245 
Reversible disc holder, 180 
Revivification of ferric oxide, 148 
Weldon mud, 170, 174 
Regenerator setting, 37 




INDEX. 


326 

Recorder, Sarco automatic, for car¬ 
bonic acid, 62, 68 
Simmance - Abady automatic, for 
carbonic acid and draught, 68 
Regulating tap to table photometer, 258, 
259, 260 

Russian oil, analysis of, for gas making, 
231 

S AMPLING furnace and waste 
gases, 44 

“ Sarco ” carbonic acid automatic 
recorder, 62, 68 
Scale of photometer, 265 
Scheibler’s calcimeter, 103 
Schilling, N. H., effusion test of the 
specific gravity of gas, 219, 220 
Schrotter apparatus, 104 
Screen, Methven, dimensions of, 178, 
179 

Secondary air supply to retort furnaces, 
43 

Seger cones used, 51, 53 
Service gas-pipe, 240 
Settings for coal-gas retort, 40, 41 
Siemens electrical pyrometer, 55, 56, 57 
Silica in fire-bricks, 164 
in fire-clays, 164 
Silver nitrate, N/10 solution, 5 
for estimation of chlorine, 6 
Silkstone coal, result of test, 17 
Simmance & Abady automatic C 0 2 
recorder, 68 

Slaking lime, increase in bulk, 106, 
107 

Sodium carbonate, N solution, 4 
Sodium thiosulphate, N solution, 5 
Sodium hydrate, combining weight, 2 
molecular weight, 2 
symbol, 2 

standard solution, 5 

Soda caustic solution, specific gravity 
and percentage, 309 
Soda lime tubes, for absorption of car¬ 
bonic acid, 97 
Solubility of ammonia, 313 


Solubility, of atmospheric air, 313 
carbon dioxide, 313 
carbon monoxide, 313 
hydrogen, 313 
nitrogen, 313 
oxygen, 313 

sulphuretted hydrogen, 313 
Soxhlet extraction apparatus for deter¬ 
mining sulphur in spent oxide, 176 
Specific gravity bottle, method of using 
for oil, 225, 226 

Specific gravity of coal, method of de¬ 
termining, 26 
of cannel gas, 10 

Specific gravity of gas, Bunsen effusion 
test, 218 

Lux balance, 219, 221 
Letheby specific gravity globe, 219 
Schilling diffusion test, 219 
Simmance-Abady bell, 222, 224 
Specific gravity of gases and vapour, 
303 

of tar, 70, 86 

of tar, determination of, 85 
Specific gravity and weights of various 
liquids, 302 

Specific heat of gases, 301, 302 
Spent lime, estimation of carbonic acid, 
no 

estimation of free lime, no, in 
Spent oxide, analysis of, 174 

estimation of sulphur, 175, 176 
estimation of ferrocyanide, 176 
Sperm candles, 182 
Sulphate of ammonia, 4, 89, 90, 91 
estimation of ammonia in, 90, 91 
estimation of moisture in, 90 
Fertilisers and Feeding Stuffs Act, 
relating to, 89 

Sulphates, estimation of, by barium 
chloride, 15 

Sulphide in gas liquor, estimation of, 
124 

Sulphite in gas liquor, estimation of, 
126 

Sulphur compounds in coal-gas, estima¬ 
tion of, 273, 274 






INDEX. 


Sulphur in coal, estimation of, 23 
in coke, estimation of, 23 
in benzene, estimation of, 293 
Sulphuretted hydrogen in crude coal- 
gas, estimation of, 95 
in purified gas, 244, 245, 272 
percentage by volume, correspond¬ 
ing to weight in grains per cubic 
foot, 315 

Sulphuric acid, combining weight, 2 
molecular weight, 2 
percentage of S 0 3 in, 306, 307, 
308 

specific gravity of, 306, 307, 308 
symbol, 2 

weight of one cubic foot, 306, 307, 
308 

Standard lamp for testing illuminating 
power, 241 
Stop clock, 264 


T ABULAR numbers for correcting 
volumes of gas, 270, 271 
Tabulated report on a sample of coal, 
20 

Tar, carburetted water-gas, 236 
coal. See Coal Tar 
effect of heat on, 70 
laboratory distillation of, 81 
separation of, from water, 83 
specific gravity of, 70, 86 
Tension, vapour, 310, 311 
Testing places, list of, 240 
Testing coal for gas making, 11 

gas for illuminating power, 241, 
243 

Thermometers, comparison of, 297, 
298 

Thiocyanate ammonium, normal solu¬ 
tion, 4 

in gas liquor, 136 
Thompson calorimeter for coke, 32 
Time and mode for testing for illumi¬ 
nating power, 241-243 


327 

TUBES, for estimation of car¬ 
bonic acid, 16 
for estimation of sulphuretted 
hydrogen, 96 

Units of heat, definition of, 316 
Univalent substances, 2 


V APOUR tension, 310, 311 

Volatile ammonia in gas liquor, 

114 

Volatile matter, determination of, 26 


W ANNER pyrometer, description 
of, 61, 62 

Water in coal, estimation, 21, 23 
in coke, estimation, 21, 23 
in oil, 230 
in oxide, 139 
in spent oxide, 175 
volume of, at different tempera¬ 
tures, 305 

Water-gas analysis, 289 
Watkins’ patent heat recorder, use of, 
50 

description, 49 
table of degrees, 51 
Weights and measures, 295 
Weldon mud, analysis of, 170 

estimation, manganese dioxide, 
172-174 

estimation, moisture, 171 
estimation of absorbing qualifica¬ 
tion for sulphuretted hydrogen, 
174 

West furnaces, 38, 40, 41, 42 
Will’s test for ammonia, 118 
Woody fibre, conversion of, 8 
composition of, 8 
decomposition of, 7 

Wright, L. T., carbonisation of coal, 
70 







328 INDEX. 


Wright, L. T., productions of cyano¬ 
gen, 71 

specific gravity of tar, 70, 72 
yield of gas at different tempera¬ 
tures, 72 

composition of tar, at different tem¬ 
peratures, 72 


^YLENE in benzole, 88 


Y IELD of coke from coal, 17, 18, 20 
gas from coal, 17, 18, 20 
gas from peat, 8, 9 
gas at various temperatures, 69, 
7 °, 72 

Young & Glover system of removing 
naphthalene in coal-gas, 162 

Z INC as a reducing agent, 144 

sulphate standard solution, 
101 


Printed at The Darien Press, Edinburgh. 




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TOWNSON & MERCER. 


Manufacturers of Scientific Apparatus, and 
Solutions for Gas Testing, and Research 
Work. 

Contractors to all the Principal Gas Companies. 

Orsat Apparatus for Flue Gases. 

Apparatus for Testing Sulphur in Spent Oxide. 

Sole Agents for Becker’s Balances. 

Complete Laboratory Furnishers. 

All Apparatus and Solutions as Gas Referees’ 
Notifications. 




Telephone—2537 LONDON WALL. 


Telegrams—"TOWNSON, LONDON.” 




























































AD VER TISEMENTS. 


iii 


JOHN ALLAN & CO.’S Publications 


DISTRIBUTION OF GAS. 

By Walter Hole. Essentially a book for the up-to-date Gas Manager. 
It contains over 700 pages and 500 Illustrations, and deals exhaustively 
with Gas Distribution in all its phases, from the Gasholder to the Con¬ 
sumer. Price 12s. 6d. net. 

“Speaking of this book as a whole, we can, with confidence, recommend it.”— 
Journal of Gas Lighting. 

SELF-INSTRUCTION FOR STUDENTS IN GAS MANU¬ 
FACTURE: Elementary, Advanced, Constructional. 

These volumes are intended for the use of Students preparing for the 
Examinations of the City and Guilds of London Institute. Crown 8vo. 
Price 3s. 6d. each net. 

MODERN RETORT SETTINGS: 

Their Construction and Working. 

By G. P. Lewis. Crown 8vo. Price 3s. 6d. net. 

THE GAS ENGINEER’S PRICE BOOK FOR ESTIMATES 
AND VALUATIONS: With Notes on the Structural 
Capacity oT Works and Plant. 

By Fred. C. Moon. Price 5s. net. 

“ THE GAS WORLD” ANALYSES OF ACCOUNTS OF GAS 
UNDERTAKINGS. (Published Annually.) 

Containing analyses of over one hundred gasworks accounts arranged on 
a novel plan, admitting of easy comparison. Price 7s. 6d. net. 

THE CITY AND GUILDS OF LONDON INSTITUTE’S 
EXAMINATIONS: Answers to some 1906 Questions. 

By Walter Grafton, Lecturer in Gas Manufacture at the Poly¬ 
technic, London, W. Price Is. 9d. net. 

GAS PROGRESS. 

A Quarterly Magazine which Gas Companies issue to consumers for 
the purpose of educating the public in the manifold uses of Gas, and its 
efficiency and economy in comparison with its rivals. It is particularly 
useful in those districts where competition is keen. Prices and full 
details will be sent on application. 


LONDON: OFFICES OF “THE GAS WORLD,’ 8 Bouverie St., E.C 








AD VERTISEMENTS. 


BROS. 

Engineers and Contractors, 

DUDLEY. 

AND 



RETORT BENCHES 

With Generator or Regenerator 

SETTINGS. 

RETORT BENCH IRONWORK COMPLETE. 



GIBBONS 



INSTALLATIONS OF INCLINED RETORTS 

COMPLETE WITH 

ELEVATING AND CONVEYING PLANT. 





AD VER TISE ME NTS. 


West s Gas Improvement Co. 

Limited, 

ENGINEERS, 

MILES PLATTING, MANCHESTER, 

And 104 QUEEN VICTORIA STREET, LONDON, E.C. 


Specialists in . . . 

Stoking Machinery for Gas Retorts, 

also 

Regenerator Furnaces and Settings. 



Coke Conveying, Breaking, and Screening Plants. 
Coal-Handling Plants of every Description. 
Gravity Bucket Conveyors. 

























VI 


A D VER TISE MENTS. 


JUST PUBLISHED. 

Small Crown 8vo, 484 pages, with Diagrams, Leather, gilt edges. 
Price 10 s. 6d. net (Postage 3d.). 


THE 

GAS ENGINEER’S 

POCKET-BOOK 


COMPRISING 

Sables, IRotes, anb flDemoranba 

RELATING TO THE 

MANUFACTURE, DISTRIBUTION, AND USE OF COAL GAS, 
AND THE CONSTRUCTION OF GAS WORKS 


BY 

HENRY O’CONNOR, 

Fellow of the Royal Society, Edinburgh; Associate Member of the Institution 
of Civil Engineers; Past President of the Society of Engineers. 


THIRD EDITION, REVISED. 


LONDON: 

CROSBY LOCKWOOD & SON 

7 Stationers’ Hall Court, Ludgate Hill. 





AD VERT[SEMENTS. 


vii 


O’CONNOR’S 

GAS ENGINEER’S POCKET BOOK 


(CONTINUED). 


EXTRACT FROM PREFACE. 

In placing this compilation before his readers, it may not be out 
of place for the author to indicate the circumstances which have led 
to the preparation of the Tables, Notes, and other matter comprised 
in the volume. 

Having frequently experienced the want of a book containing 
those numerous tables, data, &c., which are every day becoming 
more necessary to the Gas Engineer for reference, he has for many 
years been in the habit of making and preserving, for his own use, 
full notes from every available source. These notes form the basis 
of the present work, and the fact that they were originally intended 
for his own use has rendered it in many cases impossible for the 
author to acknowledge the sources of his information. 

The diagrammatic form of tabulating has been followed wher¬ 
ever it seemed to be preferable, the Tables have been most carefully 
checked, and every precaution taken to render them as accurate as 
possible. 


OPINIONS OF THE PRESS. 

“ The book contains a vast amount of information. The author goes consecu¬ 
tively through the engineering details and practical methods involved in each of 
the different processes or parts of a gas-works. He has certainly succeeded in 
making a compilation of hard matters of fact absolutely interesting to read.”— 
Gas World. 

“A useful book of reference for the gas engineer and all interested in lighting 
or heating by gas, while the analyses of the various descriptions of gas will be of 
value to the technical chemist. All matter in any way connected with the manu¬ 
facture and use of gas is dealt with. The book has evidently been carefully 
compiled, and certainly constitutes a useful addition to gas literature.”— Builder. 

“The volume contains a great quantity of specialised information, compiled, 
we believe, from trustworthy sources, which should make it of considerable value 
to those for whom it is specially produced.”— Engineer. 

“There are many features in the book which will make it welcome to those 
connected with the gas industry, and we can confidently recommend it as a useful 
and reliable companion.”— Chemical Trade Journal. 





AD VER RISE ME NTS. 




• • 
11 





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